csproj is not using latest C# version in VS 2019 [Answered]RSS

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  fletchsod2

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  csproj is not using latest C# version in VS 2019

  May 07, 2020 12:40 PM|fletchsod2|LINK

  I had upgraded the solution/projects to VS 2019 & .NET Core in all projects to netcoreapp3.1 & netstandard1.2 .  When compiled WebApp csproj is still showing older version because of this compiler error message "Program does not contain a static Main method suitable for an entry point".  I'm using async which is now permitted in C# version 8 & up.  I even try LangVersion as latest or preview w/ no luck, I read documentation that we don't need to specify LangVersion starting with .NET Core 3.0 & up as it will be done automatically.  So what could be the problem here?

  [ Program.cs ]

      public class Program

      {

          public async static void Main(string[] args)

          {

              await Host.CreateDefaultBuilder(args)

                  .ConfigureWebHostDefaults(webBuilder => {

                      webBuilder.UseContentRoot(Directory.GetCurrentDirectory());

                      webBuilder.UseKestrel();

                      webBuilder.UseAzureAppServices();

                      webBuilder.UseStartup<Startup>();

                      //webBuilder.UseSerilog()

                  })

              .ConfigureLogging((logging) =>

              {

                  //logging.AddSerilog();

              })

              .Build()

              .RunAsync();

          }

      }

  [ csproj ]

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

        <PropertyGroup>

          <VersionPrefix>1.2.0</VersionPrefix>

          <OutputType>Exe</OutputType>

          <TargetFramework>netcoreapp3.1</TargetFramework>

          <PreserveCompilationContext>true</PreserveCompilationContext>

          <AssemblyName>ABCoA.Payments.CustomerWeb</AssemblyName>

          <PackageId>ABCoA.Payments.CustomerWeb</PackageId>

        </PropertyGroup>

        <PropertyGroup>

          <LangVersion>preview</LangVersion>

        </PropertyGroup>

      </Project>

• • Reply
  PatriceSc

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  Re: csproj is not using latest C# version in VS 2019

  May 07, 2020 01:05 PM|PatriceSc|LINK

  Hi,

  Yes but it is likely done when creating a new project and here it seems an upgrade in which case it is likely left unchanged. Also you have : <LangVersion>preview</LangVersion>

  Try to use whatever you prefer from https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/configure-language-version#c-language-version-reference

  Edit: ah you changed to preview and tried a 8.0 earlier ???

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  mgebhard

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  Re: csproj is not using latest C# version in VS 2019

  May 07, 2020 01:07 PM|mgebhard|LINK

  I can't think of a good reason for a Web Application's entry point to be async.  Can you explain the problem you are trying to solve?

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  fletchsod2

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  Re: csproj is not using latest C# version in VS 2019

  May 07, 2020 01:08 PM|fletchsod2|LINK

  Hi,

  Yes but it is likely done when creating a new project and here it seems an upgrade in which case it is likely left unchanged. Also you have : <LangVersion>preview</LangVersion>

  Try to use whatever you prefer from https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/configure-language-version#c-language-version-reference

  Edit: ah you changed to preview and tried a 8.0 earlier ???

  I did create a new Web Project & updated the Main to use async.  It still fail, even though this is a clean seperation from everything else.  I even try 8.0 & latest as you suggested, still same error.

• • Reply
  fletchsod2

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  7 Posts

  Re: csproj is not using latest C# version in VS 2019

  May 07, 2020 01:11 PM|fletchsod2|LINK

  mgebhard

  I can't think of a good reason for a Web Application's entry point to be async.  Can you explain the problem you are trying to solve?

  Here's the example of why, see "RunAsync()" below.  Startting with C# 7.1 & up, the Main can be async now.  We been moving things over to async as well.

      public class Program

      {

          public async static void Main(string[] args)

          {

              await CreateHostBuilder(args).Build().RunAsync();

          }

          public static IHostBuilder CreateHostBuilder(string[] args) =>

              Host.CreateDefaultBuilder(args)

                  .ConfigureWebHostDefaults(webBuilder =>

                  {

                      webBuilder.UseStartup<Startup>();

                  });

      }

  P.S. Why is .NET forum keep adding <div></div> tags here?  How to make it not do that?

• • Reply
  mgebhard

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  Re: csproj is not using latest C# version in VS 2019

  May 07, 2020 01:28 PM|mgebhard|LINK

  I added async to the main method in a new Core 3.1 project without issue.

   

      public class Program
      {
          public static async Task Main(string[] args)
          {
              var host = CreateHostBuilder(args).Build();
  
              await host.RunAsync();
          }
  
          public static IHostBuilder CreateHostBuilder(string[] args) =>
              Host.CreateDefaultBuilder(args)
                  .ConfigureWebHostDefaults(webBuilder =>
                  {
                      webBuilder.UseStartup<Startup>();
                  });
      }

    <PropertyGroup>
      <TargetFramework>netcoreapp3.1</TargetFramework>
    </PropertyGroup>

  The latest C# compiler determines a default language version based on your project's target framework or frameworks. Visual Studio doesn't provide a UI to change the value, but you can change it by editing the csproj file.

  I still don't get the benefit of doing this.