(window.webpackJsonp=window.webpackJsonp||[]).push([[807],{1215:function(t,s,a){"use strict";a.r(s);var n=a(31),e=Object(n.a)({},(function(){var t=this,s=t.$createElement,a=t._self._c||s;return a("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[a("h1",{attrs:{id:"enum"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#enum"}},[t._v("#")]),t._v(" Enum")]),t._v(" "),a("p",[t._v("An enum can derive from any of the following types: byte, sbyte, short, ushort, int, uint, long, ulong. The default is int, and can be changed by specifying the type in the enum definition:")]),t._v(" "),a("p",[t._v("public enum Weekday : byte { Monday = 1, Tuesday = 2, Wednesday = 3, Thursday = 4, Friday = 5 }")]),t._v(" "),a("p",[t._v("This is useful when P/Invoking to native code, mapping to data sources, and similar circumstances. In general, the default int should be used, because most developers expect an enum to be an int.")]),t._v(" "),a("h2",{attrs:{id:"enum-as-flags"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#enum-as-flags"}},[t._v("#")]),t._v(" Enum as flags")]),t._v(" "),a("p",[t._v("The "),a("code",[t._v("FlagsAttribute")]),t._v(" can be applied to an enum changing the behaviour of the "),a("code",[t._v("ToString()")]),t._v(" to match the nature of the enum:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Flags")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MyEnum")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("//None = 0, can be used but not combined in bitwise operations")]),t._v("\n    FlagA "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    FlagB "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    FlagC "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    FlagD "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("8")]),t._v("  \n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("//you must use powers of two or combinations of powers of two ")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("//for bitwise operations to work")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" twoFlags "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("FlagA "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("FlagB"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v('// This will enumerate all the flags in the variable: "FlagA, FlagB".')]),t._v("\nConsole"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("twoFlags"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("p",[t._v("Because "),a("code",[t._v("FlagsAttribute")]),t._v(" relies on the enumeration constants to be powers of two (or their combinations) and enum values are ultimately numeric values, you are limited by the size of the underlying numeric type. The largest available numeric type that you can use is "),a("code",[t._v("UInt64")]),t._v(", which allows you to specify 64 distinct (non-combined) flag enum constants. The "),a("code",[t._v("enum")]),t._v(" keyword defaults to the underlying type "),a("code",[t._v("int")]),t._v(", which is "),a("code",[t._v("Int32")]),t._v(". The compiler will allow the declaration of values wider than 32 bit. Those will wrap around without a warning and result in two or more enum members of the same value. Therefore, if an enum is meant to accomodate a bitset of more than 32 flags, you need to specify a bigger type explicitely:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("BigEnum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token type-list"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("ulong")])]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    BigValue "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("63")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v('Although flags are often only a single bit, they can be combined into named "sets" for easier use.')]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Flags")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("FlagsEnum")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    None "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option3 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n       \n    Default "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Option1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Option3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    All "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Option1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Option2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Option3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("To avoid spelling out the decimal values of powers of two, the "),a("a",{attrs:{href:"https://msdn.microsoft.com/en-gb/library/a1sway8w.aspx",target:"_blank",rel:"noopener noreferrer"}},[t._v("left-shift operator (<<)"),a("OutboundLink")],1),t._v(" can also be used to declare the same enum")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Flags")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("FlagsEnum")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    None "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option3 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n       \n    Default "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Option1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Option3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    All "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Option1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Option2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Option3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("Starting with C# 7.0, "),a("a",{attrs:{href:"http://stackoverflow.com/documentation/c%23/1936/c-sharp-7-0-features/6327/binary-literals#t=201705181538117083427",target:"_blank",rel:"noopener noreferrer"}},[t._v("binary literals"),a("OutboundLink")],1),t._v(" can be used too.")]),t._v(" "),a("p",[t._v("To check if the value of enum variable has a certain flag set, the "),a("a",{attrs:{href:"https://msdn.microsoft.com/en-us/library/system.enum.hasflag(v=vs.110).aspx",target:"_blank",rel:"noopener noreferrer"}},[a("code",[t._v("HasFlag")]),a("OutboundLink")],1),t._v(" method can be used. Let's say we have")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Flags")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MyEnum")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    One "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Two "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Three "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("And a "),a("code",[t._v("value")])]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("One "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Two"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("p",[t._v("With "),a("code",[t._v("HasFlag")]),t._v(" we can check if any of the flags is set")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("HasFlag")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("One"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n    Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Enum has One"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("HasFlag")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Two"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n    Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Enum has Two"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("HasFlag")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Three"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n    Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Enum has Three"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("p",[t._v("Also we can iterate through all values of enum to get all flags that are set")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" type "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("MyEnum")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" names "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetNames")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("type"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("foreach")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" name "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("in")]),t._v(" names"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" item "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("Parse")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("type"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" name"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("HasFlag")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("item"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n        Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Enum has "')]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(" name"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("Or")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("foreach")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MyEnum")]),t._v(" flagToCheck "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("in")]),t._v(" Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetValues")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("MyEnum")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("HasFlag")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("flagToCheck"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n         Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Enum has "')]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(" flagToCheck"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("All three examples will print:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[t._v("Enum has One\nEnum has Two\n\n")])])]),a("h2",{attrs:{id:"enum-basics"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#enum-basics"}},[t._v("#")]),t._v(" Enum basics")]),t._v(" "),a("p",[t._v("From "),a("a",{attrs:{href:"https://msdn.microsoft.com/en-us/library/cc138362.aspx",target:"_blank",rel:"noopener noreferrer"}},[t._v("MSDN"),a("OutboundLink")],1),t._v(":")]),t._v(" "),a("blockquote"),t._v(" "),a("p",[t._v("An enumeration type (also named an enumeration or an enum) provides an efficient way to define a set of named "),a("strong",[t._v("integral constants")]),t._v(" that may be "),a("strong",[t._v("assigned to a variable")]),t._v(".")]),t._v(" "),a("p",[t._v("Essentially, an enum is a type that only allows a set of finite options, and each option corresponds to a number. By default, those numbers are increasing in the order the values are declared, starting from zero. For example, one could declare an enum for the days of the week:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Day")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    Monday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Tuesday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Wednesday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Thursday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Friday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Saturday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Sunday\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("That enum could be used like this:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Define variables with values corresponding to specific days")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Day")]),t._v(" myFavoriteDay "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Day"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Friday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Day")]),t._v(" myLeastFavoriteDay "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Day"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Monday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Get the int that corresponds to myFavoriteDay")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Friday is number 4")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")])]),t._v(" myFavoriteDayIndex "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("myFavoriteDay"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Get the day that represents number 5")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Day")]),t._v(" dayFive "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("Day"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("5")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("p",[t._v("By default the underlying type of each element in the "),a("code",[t._v("enum")]),t._v(" is "),a("code",[t._v("int")]),t._v(", but "),a("code",[t._v("byte")]),t._v(", "),a("code",[t._v("sbyte")]),t._v(", "),a("code",[t._v("short")]),t._v(", "),a("code",[t._v("ushort")]),t._v(", "),a("code",[t._v("uint")]),t._v(", "),a("code",[t._v("long")]),t._v(" and "),a("code",[t._v("ulong")]),t._v(" can be used as well. If you use a type other than "),a("code",[t._v("int")]),t._v(", you must specify the type using a colon after the enum name:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Day")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token type-list"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("byte")])]),t._v(" \n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// same as before ")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("The numbers after the name are now bytes instead of integers. You could get the underlying type of the enum as follows:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[t._v("Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetUnderlyingType")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("Days")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("p",[t._v("Output:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[t._v("System"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Byte\n\n")])])]),a("p",[t._v("Demo: "),a("a",{attrs:{href:"https://dotnetfiddle.net/EGi301",target:"_blank",rel:"noopener noreferrer"}},[t._v(".NET fiddle"),a("OutboundLink")],1)]),t._v(" "),a("h2",{attrs:{id:"using-notation-for-flags"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#using-notation-for-flags"}},[t._v("#")]),t._v(" Using << notation for flags")]),t._v(" "),a("p",[t._v("The left-shift operator ("),a("code",[t._v("<<")]),t._v(") can be used in flag enum declarations to ensure that each flag has exactly one "),a("code",[t._v("1")]),t._v(" in binary representation, as flags should.")]),t._v(" "),a("p",[t._v("This also helps to improve readability of large enums with plenty of flags in them.")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Flags")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MyEnum")]),t._v(" \n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    None  "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Flag1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Flag2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Flag3 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Flag4 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("3")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Flag5 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token range operator"}},[t._v("..")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("\n    Flag31 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("30")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("It is obvious now that "),a("code",[t._v("MyEnum")]),t._v(" contains proper flags only and not any messy stuff like "),a("code",[t._v("Flag30 = 1073741822")]),t._v(" (or 111111111111111111111111111110 in binary) which is inappropriate.")]),t._v(" "),a("h2",{attrs:{id:"test-flags-style-enum-values-with-bitwise-logic"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#test-flags-style-enum-values-with-bitwise-logic"}},[t._v("#")]),t._v(" Test flags-style enum values with bitwise logic")]),t._v(" "),a("p",[t._v("A flags-style enum value needs to be tested with bitwise logic because it may not match any single value.")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Flags")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("FlagsEnum")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    Option1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option3 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Option2And3 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Option2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Option3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n    Default "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Option1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Option3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("The "),a("code",[t._v("Default")]),t._v(" value is actually a combination of two others "),a("strong",[t._v("merged")]),t._v(" with a bitwise OR. Therefore to test for the presence of a flag we need to use a bitwise AND.")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" FlagsEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Default"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("bool")])]),t._v(" isOption2And3Set "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("&")]),t._v(" FlagsEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Option2And3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("==")]),t._v(" FlagsEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Option2And3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\nAssert"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("True")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("isOption2And3Set"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("h2",{attrs:{id:"enum-to-string-and-back"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#enum-to-string-and-back"}},[t._v("#")]),t._v(" Enum to string and back")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DayOfWeek")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    Sunday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Monday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Tuesday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Wednesday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Thursday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Friday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Saturday\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n    \n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Enum to string")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("string")])]),t._v(" thursday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" DayOfWeek"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Thursday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("ToString")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v('// "Thursday"')]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("string")])]),t._v(" seventhDay "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetName")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("DayOfWeek")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("6")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v('// "Saturday"')]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("string")])]),t._v(" monday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetName")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("DayOfWeek")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" DayOfWeek"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Monday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v('// "Monday"')]),t._v("\n\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// String to enum (.NET 4.0+ only - see below for alternative syntax for earlier .NET versions)")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DayOfWeek")]),t._v(" tuesday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("TryParse")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Tuesday"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("out")]),t._v(" tuesday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// DayOfWeek.Tuesday")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DayOfWeek")]),t._v(" sunday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("bool")])]),t._v(" matchFound1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("TryParse")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"SUNDAY"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("out")]),t._v(" sunday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Returns false (case-sensitive match)")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DayOfWeek")]),t._v(" wednesday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("bool")])]),t._v(" matchFound2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("TryParse")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"WEDNESDAY"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("true")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("out")]),t._v(" wednesday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Returns true; DayOfWeek.Wednesday (case-insensitive match)")]),t._v("\n\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// String to enum (all .NET versions)")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DayOfWeek")]),t._v(" friday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("DayOfWeek"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("Parse")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("DayOfWeek")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Friday"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// DayOfWeek.Friday")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DayOfWeek")]),t._v(" caturday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("DayOfWeek"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("Parse")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("DayOfWeek")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Caturady"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Thows ArgumentException")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// All names of an enum type as strings")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("string")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")])]),t._v(" weekdays "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetNames")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("DayOfWeek")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("h2",{attrs:{id:"add-and-remove-values-from-flagged-enum"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#add-and-remove-values-from-flagged-enum"}},[t._v("#")]),t._v(" Add and remove values from flagged enum")]),t._v(" "),a("p",[t._v("This code is to  add and remove a value from a flagged enum-instance:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Flags")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MyEnum")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    Flag1 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Flag2 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Flag3 "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<<")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Flag1"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// set additional value")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|=")]),t._v(" MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Flag2"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("  "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("//value is now Flag1, Flag2")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|=")]),t._v(" MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Flag3"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("  "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("//value is now Flag1, Flag2, Flag3")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// remove flag")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("value")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("&=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("~")]),t._v("MyEnum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Flag2"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("//value is now Flag1, Flag3    ")]),t._v("\n\n")])])]),a("h2",{attrs:{id:"default-value-for-enum-zero"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#default-value-for-enum-zero"}},[t._v("#")]),t._v(" Default value for enum == ZERO")]),t._v(" "),a("p",[a("strong",[t._v("The default value for an enum is zero")]),t._v(".  If an enum does not define an item with a value of zero, its default value will be zero.")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("class")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Program")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("        \n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("EnumExample")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        one "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n        two "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n    \n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token return-type class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("Main")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("              \n        "),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" e "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("default")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("EnumExample")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        \n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("e "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("==")]),t._v(" EnumExample"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("one"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n            Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"defaults to one"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("else")]),t._v("\n            Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Unknown"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("    \n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("    \n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("Example:\n"),a("a",{attrs:{href:"https://dotnetfiddle.net/l5Rwie",target:"_blank",rel:"noopener noreferrer"}},[t._v("https://dotnetfiddle.net/l5Rwie"),a("OutboundLink")],1)]),t._v(" "),a("h2",{attrs:{id:"adding-additional-description-information-to-an-enum-value"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#adding-additional-description-information-to-an-enum-value"}},[t._v("#")]),t._v(" Adding additional description information to an enum value")]),t._v(" "),a("p",[t._v("In some cases you might want to add an additional description to an enum value, for instance when the enum value itself is less readable than what you might want to display to the user. In such cases you can use the "),a("a",{attrs:{href:"https://msdn.microsoft.com/en-us/library/system.componentmodel.descriptionattribute(v=vs.110).aspx",target:"_blank",rel:"noopener noreferrer"}},[a("code",[t._v("System.ComponentModel.DescriptionAttribute")]),a("OutboundLink")],1),t._v(" class.")]),t._v(" "),a("p",[t._v("For example:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("PossibleResults")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Description")]),a("span",{pre:!0,attrs:{class:"token attribute-arguments"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Success"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")])])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n    OK "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Description")]),a("span",{pre:!0,attrs:{class:"token attribute-arguments"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"File not found"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")])])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n    FileNotFound "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Description")]),a("span",{pre:!0,attrs:{class:"token attribute-arguments"}},[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token string"}},[t._v('"Access denied"')]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")])])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n    AccessDenied "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("3")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("Now, if you would like to return the description of a specific enum value you can do the following:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("static")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token return-type class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("string")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetDescriptionAttribute")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("PossibleResults")]),t._v(" result"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("return")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("DescriptionAttribute"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("Attribute"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetCustomAttribute")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("result"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetType")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetField")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("result"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("ToString")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("DescriptionAttribute")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Description"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("static")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token return-type class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("void")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("Main")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("string")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")])]),t._v(" args"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("PossibleResults")]),t._v(" result "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" PossibleResults"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("FileNotFound"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("result"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v('// Prints "FileNotFound"')]),t._v("\n    Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetDescriptionAttribute")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("result"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v('// Prints "File not found"')]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("This can also be easily transformed to an extension method for all enums:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("static")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("class")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("EnumExtensions")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("static")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token return-type class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("string")])]),t._v(" "),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetDescription")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("this")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Enum")]),t._v(" enumValue"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("return")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("DescriptionAttribute"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("Attribute"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetCustomAttribute")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("enumValue"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetType")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetField")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("enumValue"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("ToString")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("DescriptionAttribute")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Description"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n")])])]),a("p",[t._v("And then easily used like this:\n"),a("code",[t._v("Console.WriteLine(result.GetDescription());")])]),t._v(" "),a("h2",{attrs:{id:"enums-can-have-unexpected-values"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#enums-can-have-unexpected-values"}},[t._v("#")]),t._v(" Enums can have unexpected values")]),t._v(" "),a("p",[t._v("Since an enum can be cast to and from its underlying integral type, the value may fall outside the range of values given in the definition of the enum type.")]),t._v(" "),a("p",[t._v("Although the below enum type "),a("code",[t._v("DaysOfWeek")]),t._v(" only has 7 defined values, it can still hold any "),a("code",[t._v("int")]),t._v(" value.")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DaysOfWeek")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    Monday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Tuesday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Wednesday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("3")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Thursday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Friday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("5")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Saturday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("6")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Sunday "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("7")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DaysOfWeek")]),t._v(" d "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("DaysOfWeek"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("31")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nConsole"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("d"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// prints 31")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DaysOFWeek")]),t._v(" s "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" DaysOfWeek"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Sunday"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\ns"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("++")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// No error")]),t._v("\n\n")])])]),a("p",[t._v("There is currently no way to define an enum which does not have this behavior.")]),t._v(" "),a("p",[t._v("However, undefined enum values can be detected by using the method "),a("code",[t._v("Enum.IsDefined")]),t._v(". For example,")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("DaysOfWeek")]),t._v(" d "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("DaysOfWeek"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("31")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nConsole"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("IsDefined")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("DaysOfWeek")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("d"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// prints False")]),t._v("\n\n")])])]),a("h2",{attrs:{id:"get-all-the-members-values-of-an-enum"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#get-all-the-members-values-of-an-enum"}},[t._v("#")]),t._v(" Get all the members values of an enum")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MyEnum")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    One"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Two"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Three\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("foreach")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MyEnum")]),t._v(" e "),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("in")]),t._v(" Enum"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("GetValues")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("typeof")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token type-expression class-name"}},[t._v("MyEnum")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n    Console"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("e"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("p",[t._v("This will print:")]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[t._v("One\nTwo\nThree\n\n")])])]),a("h2",{attrs:{id:"bitwise-manipulation-using-enums"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#bitwise-manipulation-using-enums"}},[t._v("#")]),t._v(" Bitwise Manipulation using enums")]),t._v(" "),a("p",[t._v("The "),a("a",{attrs:{href:"https://msdn.microsoft.com/en-us/library/system.flagsattribute(v=vs.110).aspx",target:"_blank",rel:"noopener noreferrer"}},[t._v("FlagsAttribute"),a("OutboundLink")],1),t._v(" should be used whenever the enumerable represents a collection of flags, rather than a single value.\nThe numeric value assigned to each enum value helps when manipulating enums using bitwise operators.")]),t._v(" "),a("p",[a("strong",[t._v("Example 1 : With [Flags]")])]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),a("span",{pre:!0,attrs:{class:"token attribute"}},[a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Flags")])]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Colors")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    Red"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Blue"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Green"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Yellow"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("8")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" color "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Colors"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Red "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Colors"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Blue"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nConsole"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("color"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("ToString")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("blockquote"),t._v(" "),a("p",[t._v("prints Red,Blue")]),t._v(" "),a("p",[a("strong",[a("strong",[t._v("Example 2 : Without [Flags]")])])]),t._v(" "),a("div",{staticClass:"language-cs extra-class"},[a("pre",{pre:!0,attrs:{class:"language-cs"}},[a("code",[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("enum")]),t._v(" "),a("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Colors")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n    Red"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("1")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Blue"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Green"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("4")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n    Yellow"),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),a("span",{pre:!0,attrs:{class:"token number"}},[t._v("8")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token class-name"}},[a("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("var")])]),t._v(" color "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" Colors"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Red "),a("span",{pre:!0,attrs:{class:"token operator"}},[t._v("|")]),t._v(" Colors"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("Blue"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nConsole"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("WriteLine")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("color"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),a("span",{pre:!0,attrs:{class:"token function"}},[t._v("ToString")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("blockquote"),t._v(" "),a("p",[t._v("prints 3")]),t._v(" "),a("h4",{attrs:{id:"syntax"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#syntax"}},[t._v("#")]),t._v(" Syntax")]),t._v(" "),a("ul",[a("li",[t._v("enum Colors { Red, Green, Blue } // Enum declaration")]),t._v(" "),a("li",[t._v("enum Colors : byte { Red, Green, Blue } // Declaration with specific type")]),t._v(" "),a("li",[t._v("enum Colors { Red = 23, Green = 45, Blue = 12 } // Declaration with defined values")]),t._v(" "),a("li",[t._v("Colors.Red // Access an element of an Enum")]),t._v(" "),a("li",[t._v("int value = (int)Colors.Red // Get the int value of an enum element")]),t._v(" "),a("li",[t._v("Colors color = (Colors)intValue // Get an enum element from int")])]),t._v(" "),a("h4",{attrs:{id:"remarks"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#remarks"}},[t._v("#")]),t._v(" Remarks")]),t._v(" "),a("p",[t._v('An Enum (short for "enumerated type") is a type consisting of a set of named constants, represented by a type-specific identifier.')]),t._v(" "),a("p",[t._v("Enums are most useful for representing concepts that have a (usually small) number of possible discrete values. For example, they can be used to represent a day of the week or a month of the year. They can be also be used as flags which can be combined or checked for, using bitwise operations.")])])}),[],!1,null,null,null);s.default=e.exports}}]);