How can I use C# 8 with Visual Studio 2017?

Question

I'd like to use C# 8.0 (especially ranges and non-nullable reference types) in Visual Studio 2017. Is it possible?

Answer 1

Going forward, Microsoft want to tie C# language versions more closely to framework versions than they have in the past. They really only want you to be using C# 8 with .NET Core 3.x and .NET Standard 2.1 projects, and that means using Visual Studio 2019. My answer to Does C# 8 support the .NET Framework? has all the gory details.

However, if you really want to you can now use C# 8 in Visual Studio 2017 by using the same trick that brings C# 7 to Visual Studio 2015: install the latest version of the Microsoft.Net.Compilers Nuget package into the project. It works, but of course VS 2017 doesn't know about C# 8 syntax so it doesn't look very pretty. Here's a screenshot showing that VS 2017 is able to compile a small test library using nullable reference types and a static local method (both of which are C# 8 features):

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Here's the .csproj and code if you want to try it:

<Project Sdk="Microsoft.NET.Sdk">   <PropertyGroup>     <TargetFrameworks>netstandard2.0;net452</TargetFrameworks>     <LangVersion>8.0</LangVersion>         <Nullable>enable</Nullable>   </PropertyGroup>   <ItemGroup>     <PackageReference Include="Microsoft.Net.Compilers" Version="3.3.1">       <PrivateAssets>all</PrivateAssets>       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>     </PackageReference>   </ItemGroup> </Project> 

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using System;  namespace CSharp8Test {     public class Class1     {         public string? NullableString { get; } = "Test";          public static void Test()         {             Console.WriteLine(Test2());             static int Test2() => 5;         }     } } 

Answer 2

Add on to series0ne's comment about the major releases: It is true that new VS usually ship with new C# version. However, in the past experience, it is possible to upgrade previous version of VS to compiler newer version of C# code, mainly by upgrading the "Microsoft.Net.Compilers" Nuget package. You may reference to this post for more information. How to use c#7 with Visual Studio 2015?