Unable to generate an exe file with Roslyn.

[bul71]

I'm a Roslyn noob. I'm not able to build properlly an exe file from inside my app. It just makes a 0 octet exe whom acces permission is denied. What do I do wrong ?

[333fred]

You'll need to provide more details for us to help you with this.

[bul71]

// Here is my humble code. It's a gathering from different Internet sources :
// --------------------------------------------------------------------------------

public void CompileCode_UserToExe(string code, string sExeOut)
{
    var syntaxTree = CSharpSyntaxTree.ParseText(code);

    var references = AppDomain.CurrentDomain.GetAssemblies()
        .Where(a => !a.IsDynamic && !string.IsNullOrEmpty(a.Location))
        .Select(a => MetadataReference.CreateFromFile(a.Location))
        .Cast<MetadataReference>()
        .ToList();

    var compilationOptions = new CSharpCompilationOptions(
        OutputKind.WindowsApplication,
        mainTypeName: "Program"  // Make sure the Main method is in a class named Program

    ).WithPlatform(Platform.AnyCpu).WithOptimizationLevel(OptimizationLevel.Release);

    var compilation = CSharpCompilation.Create("MyApp")
        .WithOptions(compilationOptions)
        .AddReferences(references)
        .AddSyntaxTrees(syntaxTree);

    var pathToExe = sExeOut;
    var result = compilation.Emit(pathToExe);

    if (result.Success)
    {
        // I don't need to start the exe now. Just to remember how to do it.
        //Process.Start(pathToExe);
    }
    else
    {
        foreach (var diagnostic in result.Diagnostics)
        {
            Console.WriteLine(diagnostic.ToString());
        }
    }
}//public void CompileCode_UserToExe(string code, string sExeOut)

[333fred]

So, first and foremost, we don't recommend what you're doing to get reference assemblies. Use https://github.com/jaredpar/basic-reference-assemblies instead. Beyond that, whatever you're doing wrong isn't with that code. Here's a complete example that adapts nearly your exact code and runs just fine, producing /tmp/MyApp.exe exactly where it should:

Program.cs

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;

CompileCode_UserToExe("""
    using System;
    class Program
    {
        static void Main()
        {
            Console.WriteLine("Hello, World!");
        }
    }
    """, "/tmp/test/MyApp.exe");

void CompileCode_UserToExe(string code, string sExeOut)
{
    var syntaxTree = CSharpSyntaxTree.ParseText(code);

    var references = Basic.Reference.Assemblies.Net80.References.All;

    var compilationOptions = new CSharpCompilationOptions(
        OutputKind.WindowsApplication,
        mainTypeName: "Program"  // Make sure the Main method is in a class named Program
    ).WithPlatform(Platform.AnyCpu).WithOptimizationLevel(OptimizationLevel.Release);

    var compilation = CSharpCompilation.Create("MyApp")
        .WithOptions(compilationOptions)
        .AddReferences(references)
        .AddSyntaxTrees(syntaxTree);

    var pathToExe = sExeOut;
    var result = compilation.Emit(pathToExe);

    if (result.Success)
    {
        // I don't need to start the exe now. Just to remember how to do it.
        //Process.Start(pathToExe);
        Console.WriteLine("Success!");
    }
    else
    {
        foreach (var diagnostic in result.Diagnostics)
        {
            Console.WriteLine(diagnostic.ToString());
        }
    }
}//public void CompileCode_UserToExe(string code, string sExeOut)

test.csproj

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

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net9.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Basic.Reference.Assemblies" Version="1.7.2" />
    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.10.0" />
  </ItemGroup>

</Project>