C# 9–Use Record types in .NET Standard 2.0

I created a small Record type in C#:

	public record MenuCode
	{
	public string Uri { get; init; }
	public string MenuId { get; init; }
	}

view raw MenuCode.cs hosted with ❤ by GitHub

However the compiler didn’t like it:

Why? Because I was adding this code to a .NET Standard 2.0 library that doesn’t support C# 9 features.

As a reminder, a small overview:

Target framework Version	C# Language Version
.NET 5	C# 9.0
.NET Core 3.x	C# 8.0
.NET Core 2.x	C# 7.3
.NET Standard 2.1	C# 8.0
.NET Standard 2.0	C# 7.3

I didn’t want to upgrade to .NET 5 so what are my options? Turns out, that you can work around this with a small compiler hack…

Let’s try it:

• First you need to override the language version in the csproj file:

	<PropertyGroup>
	<LangVersion>9.0</LangVersion>
	</PropertyGroup>

view raw Langversion.csproj hosted with ❤ by GitHub

• Then you should add the following code to get rid of the compiler error:

	namespace System.Runtime.CompilerServices
	{
	public class IsExternalInit { }
	}

view raw IsExternalInit.cs hosted with ❤ by GitHub