在 .NET Core 1.0 中运行时编译和运行代码

Question

是否可以在运行新的 .NET Core（更好的 .NET 标准平台）中编译和运行 C# 代码？

我看过一些示例（.NET Framework），但它们使用的 NuGet 包与 netcoreapp1.0 (.NETCoreApp,Version=v1.0)

Answer 1

选项 #1：使用完整的 C# 编译器编译程序集，加载它，然后从中执行方法。

这需要以下包作为您 project.json 中的依赖项：

"Microsoft.CodeAnalysis.CSharp": "1.3.0-beta1-20160429-01",
"System.Runtime.Loader": "4.0.0-rc2-24027",

然后你可以使用这样的代码：

var compilation = CSharpCompilation.Create("a")
    .WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
    .AddReferences(
        MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location))
    .AddSyntaxTrees(CSharpSyntaxTree.ParseText(
        @"
using System;

public static class C
{
    public static void M()
    {
        Console.WriteLine(""Hello Roslyn."");
    }
}"));

var fileName = "a.dll";

compilation.Emit(fileName);

var a = AssemblyLoadContext.Default.LoadFromAssemblyPath(Path.GetFullPath(fileName));

a.GetType("C").GetMethod("M").Invoke(null, null);

选项 #2：使用 Roslyn 脚本。这将导致代码更简单，但目前需要更多设置：

创建 NuGet.config 以从 Roslyn 夜间提要获取包：

  <?xml version="1.0" encoding="utf-8"?>
  <configuration>
    <packageSources>
      <add key="Roslyn Nightly" value="https://www.myget.org/F/roslyn-nightly/api/v3/index.json" />
    </packageSources>
  </configuration>

将以下包作为依赖添加到project.json（注意这是今天的包，以后需要不同的版本):
```
  "Microsoft.CodeAnalysis.CSharp.Scripting": "1.3.0-beta1-20160530-01",
```
您还需要导入 dotnet（过时的“Target Framework Moniker”，which is nevertheless still used by Roslyn）：
```
  "frameworks": {
    "netcoreapp1.0": {
      "imports": "dotnet5.6"
    }
  }
```

现在终于可以使用脚本了：

  CSharpScript.EvaluateAsync(@"using System;Console.WriteLine(""Hello Roslyn."");").Wait();

Answer 2

我只是添加到。如果您想将程序集保存在内存中（而不是写入文件），您可以使用以下方法：

AssemblyLoadContext context = AssemblyLoadContext.Default;
Assembly assembly = context.LoadFromStream(ms);

这与 .NET 4.5.1 中的代码不同：

Assembly assembly = Assembly.Load(ms.ToArray());

我的代码同时针对 .NET 4.5.1 和 .NET Standard，因此我不得不使用指令来解决这个问题。完整的代码示例在这里：

string code = CreateFunctionCode();
var syntaxTree = CSharpSyntaxTree.ParseText(code);

MetadataReference[] references = new MetadataReference[]
{
    MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location),
    MetadataReference.CreateFromFile(typeof(Hashtable).GetTypeInfo().Assembly.Location)
};

var compilation = CSharpCompilation.Create("Function.dll",
   syntaxTrees: new[] { syntaxTree },
   references: references,
   options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));

StringBuilder message = new StringBuilder();

using (var ms = new MemoryStream())
{
    EmitResult result = compilation.Emit(ms);

    if (!result.Success)
    {
        IEnumerable<Diagnostic> failures = result.Diagnostics.Where(diagnostic =>
            diagnostic.IsWarningAsError ||
            diagnostic.Severity == DiagnosticSeverity.Error);

        foreach (Diagnostic diagnostic in failures)
        {
            message.AppendFormat("{0}: {1}", diagnostic.Id, diagnostic.GetMessage());
        }

        return new ReturnValue<MethodInfo>(false, "The following compile errors were encountered: " + message.ToString(), null);
    }
    else
    {
        ms.Seek(0, SeekOrigin.Begin);

        #if NET451
            Assembly assembly = Assembly.Load(ms.ToArray());
        #else
            AssemblyLoadContext context = AssemblyLoadContext.Default;
            Assembly assembly = context.LoadFromStream(ms);
        #endif

        Type mappingFunction = assembly.GetType("Program");
        _functionMethod = mappingFunction.GetMethod("CustomFunction");
        _resetMethod = mappingFunction.GetMethod("Reset");
    }
}

Answer 3

之前的两个答案在 Windows 上的 .NET Core 2.2 环境中对我都不起作用。需要更多参考资料。

所以在解决方案的帮助下，我得到了这段代码：

var dotnetCoreDirectory = System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory();

var compilation = CSharpCompilation.Create("LibraryName")
    .WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary))
    .AddReferences(
        MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location),
        MetadataReference.CreateFromFile(typeof(Console).GetTypeInfo().Assembly.Location),
        MetadataReference.CreateFromFile(Path.Combine(dotnetCoreDirectory, "mscorlib.dll")),
        MetadataReference.CreateFromFile(Path.Combine(dotnetCoreDirectory, "netstandard.dll")),
        MetadataReference.CreateFromFile(Path.Combine(dotnetCoreDirectory, "System.Runtime.dll")))
    .AddSyntaxTrees(CSharpSyntaxTree.ParseText(
        @"public static class ClassName
        {
            public static void MethodName() => System.Console.WriteLine(""Hello C# Compilation."");
        }"));

// Debug output. In case your environment is different it may show some messages.
foreach (var compilerMessage in compilation.GetDiagnostics())
    Console.WriteLine(compilerMessage);

比输出库到文件：

var fileName = "LibraryName.dll";
var emitResult = compilation.Emit(fileName);
if (emitResult.Success)
{
    var assembly = AssemblyLoadContext.Default.LoadFromAssemblyPath(Path.GetFullPath(fileName));

    assembly.GetType("ClassName").GetMethod("MethodName").Invoke(null, null);
}

或内存流：

using (var memoryStream = new MemoryStream())
{
    var emitResult = compilation.Emit(memoryStream);
    if (emitResult.Success)
    {
        memoryStream.Seek(0, SeekOrigin.Begin);

        var context = AssemblyLoadContext.Default;
        var assembly = context.LoadFromStream(memoryStream);

        assembly.GetType("ClassName").GetMethod("MethodName").Invoke(null, null);
    }
}

在 .NET Core 1.0 中运行时编译和运行代码

Compiling and running code at runtime in .NET Core 1.0

c#

.net-core

.net-core-rc2

在 .NET Core 1.0 中运行时编译和 运行 代码

Compiling and running code at runtime in .NET Core 1.0

c#

.net-core

.net-core-rc2

在 .NET Core 1.0 中运行时编译和运行代码