Migrated view model List<> properties to use Collection<>

JeremyCaney · JeremyCaney · commit 86fd5c4855dc · 2020-12-16T17:23:54.000-08:00
Microsoft's design guidelines recommend that public interfaces use `Collection<T>` instead of `List<T>` (CA1002). The `List<T>` type is faster, and optimized for performance, but includes a lot of low-level members that most users don't need, while `Collection<T>` has more high-level convenience members that are more intuitive for most users. As this was a breaking change, however, we didn't implement this as part of our implementation of Microsoft's updated Code Analysis (27e6940). Now that we're preparing for a major release, we're able to make these changes which could potentially break some implementations. Notably, this will break implementations that specifically access the member as a `List<T>` (e.g., as a cast or assignment), or which call some of the `List<T>` specific methods, such as `AddRange()`. These calls were previously removed from elsewhere in the OnTopic library in preparation for this migration, but may still persist in some client implementations.
diff --git a/OnTopic.Tests/ViewModels/CompatiblePropertyTopicViewModel.cs b/OnTopic.Tests/ViewModels/CompatiblePropertyTopicViewModel.cs
@@ -4,7 +4,7 @@
 | Project       Topics Library
 \=============================================================================================================================*/
 using System;
-using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Diagnostics.CodeAnalysis;
 using OnTopic.Metadata;
 
@@ -25,9 +25,7 @@ public class CompatiblePropertyTopicViewModel {
 
     public ModelType ModelType { get; set; }
 
-    #pragma warning disable CA1002 // Do not expose generic lists
-    public List<DateTime>? VersionHistory { get; set; }
-    #pragma warning restore CA1002 // Do not expose generic lists
+    public Collection<DateTime>? VersionHistory { get; set; }
 
   } //Class
 } //Namespace
diff --git a/OnTopic/GlobalSuppressions.cs b/OnTopic/GlobalSuppressions.cs
@@ -7,5 +7,4 @@
 
 [assembly: SuppressMessage("Globalization", "CA1307:Specify StringComparison", Justification = "StringComparison overload not supported by .NET Standard 2.0", Scope = "member", Target = "~M:OnTopic.Topic.GetWebPath~System.String")]
 [assembly: SuppressMessage("Usage", "CA2249:Consider using 'string.Contains' instead of 'string.IndexOf'", Justification = "StringComparison overload not supported by .NET Standard 2.0.", Scope = "member", Target = "~M:OnTopic.Querying.TopicExtensions.FindAllByAttribute(OnTopic.Topic,System.String,System.String)~OnTopic.Collections.ReadOnlyTopicCollection{OnTopic.Topic}")]
-[assembly: SuppressMessage("Naming", "CA1711:Identifiers should not have incorrect suffix", Justification = "Expected by convention for OnTopic Editor", Scope = "namespaceanddescendants", Target = "~N:OnTopic")]
-[assembly: SuppressMessage("Design", "CA1002:Do not expose generic lists", Justification = "Breaking change; deferred to major version.", Scope = "namespaceanddescendants", Target = "~N:OnTopic")]
+[assembly: SuppressMessage("Naming", "CA1711:Identifiers should not have incorrect suffix", Justification = "Expected by convention for OnTopic Editor", Scope = "namespaceanddescendants", Target = "~N:OnTopic")]
diff --git a/OnTopic/Internal/Reflection/TypeMemberInfoCollection.cs b/OnTopic/Internal/Reflection/TypeMemberInfoCollection.cs
@@ -454,7 +454,7 @@ private static bool IsSettableType(Type sourceType, Type? targetType = null) {
     /// <summary>
     ///   A list of types that are allowed to be set using <see cref="SetPropertyValue(Object, String, String)"/>.
     /// </summary>
-    public static List<Type> SettableTypes { get; }
+    public static Collection<Type> SettableTypes { get; }
 
     /*==========================================================================================================================
     | OVERRIDE: INSERT ITEM
diff --git a/OnTopic/Topic.cs b/OnTopic/Topic.cs
@@ -5,6 +5,7 @@
 \=============================================================================================================================*/
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Linq;
@@ -644,7 +645,7 @@ public Topic? DerivedTopic {
     ///   its derived providers).
     /// </remarks>
     /// <value>The current <see cref="Topic"/>'s version history.</value>
-    public List<DateTime> VersionHistory { get; }
+    public Collection<DateTime> VersionHistory { get; }
 
     #endregion
 
