How enable C# 9.0 Features on Visual Studio 16.8.3?

Question

I currently use Visual Studio 2019 build 16.8.3. I understand that C# 9.0 features should be available on that platform now. However, if I try to declare a 'record' type in Visual Studio, it shows an error. For example:

namespace Records
{
    public record Person
    {

    }

} // namespace Records

It shows squiggly red lines under 'record' and 'person'. The record error is CS0246: The type or namespace name 'record' could not be found... The Person error is CS0116: A namespace cannot directly contain members such as fields or method and CD0548: '<invalid-global-code>.Person': property or indexer must have at least one accessor.

How do I get Visual Studio to recognize and use C# 9.0 features?

Thanks.

Answer 1

In the Properties for the project, what setting do you have here?

Build->Advanced->Language version

• Wayne

Answer 2

It won't let me change the 'Language version'. Says: Automatically selected based on framework version. I edited the .csproj file to change the framework version from 'netcoreapp3.1' to 'netcoreapp5.0' and that fixed the problem. Thanks for the help.

Answer 3

For SDK Style projects <LangVersion> can be set to latest as below in csproj file

<Project Sdk="Microsoft.NET.Sdk">

    <PropertyGroup>
        <TargetFramework>netstandard2.1</TargetFramework>
        <LangVersion>latest</LangVersion>
    </PropertyGroup>

</Project>

Answer 4

Sorry, I solved this problem a few months ago. We can close this question.