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CsvExport

A very simple and very fast CSV-export tool for C#.

.NET

V3 Breaking changes:

  • .NET 8 targeting (use v2 for .NET Framework, we'll backport critical fixes)
  • Uses char instead of string for column separator

Features

  1. Excel-compatible export (separator detected automatically, friendly-trimming rows and values for compatibility)
  2. Escapes commas, quotes, multiline text
  3. Exports dates in timezone-proof format
  4. Extremely easy to use
  5. 30 times faster than CsvHelper
  6. 4-times less memory usage

Benchmarks

Method Mean Error StdDev Gen0 Gen1 Allocated
😟 CsvHelper 372.90 us 390.842 us 21.423 us 9.7656 4.8828 85.4 KB
✅ CsvExport_Manual 12.71 us 1.040 us 0.057 us 3.5858 0.1984 29.35 KB
✅ CsvExport_GenericType 13.22 us 1.240 us 0.068 us 3.5858 0.2289 29.39 KB

This benchmark is generating a 100-line CSV file with 4 columns. Check the "SpeedBenchmarks" code.

Usage examples:

Install via Nuget Install-Package CsvExport

For "manual" CSV ad-hoc generation use this:

var myExport = new CsvExport();

myExport.AddRow();
myExport["Region"] = "Los Angeles, USA";
myExport["Sales"] = 100000;
myExport["Date Opened"] = new DateTime(2003, 12, 31);

myExport.AddRow();
myExport["Region"] = "Canberra \"in\" Australia";
myExport["Sales"] = 50000;
myExport["Date Opened"] = new DateTime(2005, 1, 1, 9, 30, 0);

//save as file
myExport.ExportToFile("results.csv");

For generating CSV out of a typed List<T> of objects:

public class Foo
{
	public string Region { get; set; }
	public int Sales { get; set; }
	public DateTime DateOpened { get; set; }
}

var list = new List<Foo>
{
	new Foo { Region = "Los Angeles", Sales = 123321, DateOpened = DateTime.Now },
	new Foo { Region = "Canberra in Australia", Sales = 123321, DateOpened = DateTime.Now },
};

var myExport = new CsvExport();
myExport.AddRows(list);
string csv = myExport.Export();

Configuring is done via constructor parameters:

var myExport = new CsvExport(
	columnSeparator: ',',
	includeColumnSeparatorDefinitionPreamble: true, //Excel wants this in CSV files
	includeHeaderRow: true
);

Also, methods ExportToFile and WriteToStream and ExportToBytes offer an optional encoding parameter.

Using with ASP.NET Core:

For big CSV files (megabytes) use WriteToStreamAsync and write to Response.Body directly. This is very important to save memory usage. Here's a handy heper class:

public class CsvExportResult(Csv.CsvExport csv, string fileName) : ActionResult
{
	public override Task ExecuteResultAsync(ActionContext ctx)
	{
		var res = ctx.HttpContext.Response;
		res.ContentType = "text/csv";
		res.Headers.ContentDisposition = $"attachment; filename=\"{fileName}\"";
		return csv.WriteToStreamAsync(res.Body, cancellationToken: ctx.HttpContext.RequestAborted);
	}
}

//usage in MVC action
return new CsvExportResult(csvExport, "filename.csv");

License

The code is licensed under MIT License.

Sucessfully tested for years in production with our Jitbit Helpdesk Ticketing System