CODEWITHSUNDEEP
c#roslyn
Michiel Overeem
Michiel Overeem

Reputation: 3992

Compiling .NET Core App with Roslyn API

I am generating some dynamic C# and want to compile it to a .NET Core App. However, it seems that the deps.json file is missing to make it actually runnable. So the compiling itself works, but on running dotnet [name of dll] it gives an error:

In code I do

  CSharpCompilation compilation = CSharpCompilation.Create(assemblyName,
    syntaxTrees: files,
    references: references,
    options: new CSharpCompilationOptions(OutputKind.ConsoleApplication,
      optimizationLevel: OptimizationLevel.Debug
    )
  );

  FileUtility.CreateDirectory(outputDllPath);
  EmitResult result = compilation.Emit(outputDllPath, pdbPath: outputPdbPath);

The references collection contains Microsoft.NETCore.App and the netstandard 2.0.0 ref dll, besides other specific dll's that are netstandard2.0 compliant.

This works without errors. On running I get:

Unhandled Exception: System.TypeLoadException: Could not load type 'System.Object' from assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.

How do I produce the correct deps.json file for my compilation?

Upvotes: 5

Views: 2372

Answers (1)

Michiel Overeem
Michiel Overeem

Reputation: 3992

We solved it by doing the following things:

Compile the C# files against the dll's from C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.netcore.app\2.0.0\ref\netcoreapp2.0 (don't add references to .NET 4. dll's!):

public static IEnumerable<PortableExecutableReference> CreateNetCoreReferences()
{
  foreach(var dllFile in Directory.GetFiles(@"C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.netcore.app\2.0.0\ref\netcoreapp2.0", "*.dll"))
  {
    yield return MetadataReference.CreateFromFile(dllFile);
  }
}

Create a CSharpCompilation with a ConsoleApp as output:

CSharpCompilation.Create(assemblyName,
    syntaxTrees: files,
    references: references,
    options: new CSharpCompilationOptions(OutputKind.ConsoleApplication)
  );

Now you only need to place runtimeconfig.json ([dllname].runtimeconfig.json) next to the output, with the following content:

{
  "runtimeOptions": {
    "tfm": "netcoreapp2.0",
    "framework": {
      "name": "Microsoft.NETCore.App",
      "version": "2.0.0"
    }
  }
}

The output can be run with dotnet.exe.

Upvotes: 3

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