使用 Reflection.Emit / Sigil 的构造函数链接

Question

我正在尝试使用 Sigil 创建一个如下所示的 class，它是 Reflection.Emit.

的包装器

public class Test
{
    public Test(string arg1)
    {
    }

    public Test() : this("arg1") 
    {
    }
}

使用以下代码我不断收到异常："The invoked member is not supported before the type is created."

using System;
using System.Reflection;
using System.Reflection.Emit;
using Sigil.NonGeneric;

public class Program
{
    public static void Main()
    {
        var asmName = new AssemblyName("MyAssembly");
        var asm = AppDomain.CurrentDomain.DefineDynamicAssembly(asmName, AssemblyBuilderAccess.Save);

        var mod = asm.DefineDynamicModule(asmName.Name, asmName.Name + ".dll");

        var test = mod.DefineType("Test", TypeAttributes.Public);

        // special constructor
        var ctorBuilder1 = Emit.BuildConstructor(new Type[] { typeof(string) }, test, MethodAttributes.Public);
        ctorBuilder1.Return();
        var ctor1 = ctorBuilder1.CreateConstructor();

        // default constructor calling the special one
        var ctorBuilder2 = Emit.BuildConstructor(new Type[] { }, test, MethodAttributes.Public);
        ctorBuilder2.LoadArgument(0);
        ctorBuilder2.LoadConstant("arg1");
        ctorBuilder2.Call(ctor1); // Exception thrown here
        ctorBuilder2.Return();
        var ctor2 = ctorBuilder2.CreateConstructor();

        test.CreateType();
        asm.Save(asmName.Name + ".dll");
    }
}

我阅读了有关使用“DynamicMethod”的信息，但是当我用以下内容替换 BuildConstructor 调用时出现错误 "Delegate of type Sigil.Impl.NonGenericPlaceholderDelegate takes no parameters"：

var piCtor = Emit.NewDynamicMethod(pi, new Type[] {}, ".ctor", mod);

感谢您的帮助。

Answer 1

目前看来，至少 Sigil.NonGeneric没有正确处理这个问题。但是，看起来您也可以将 Sigil 与非 Sigil 代码混合搭配。

所以你可以改变只是你的ctorBuilder2代码以使用内置Reflection.Emit代码：

var ctorBuilder2 = test.DefineConstructor(MethodAttributes.Public,
    CallingConventions.Standard, new Type[0]);
var generator = ctorBuilder2.GetILGenerator();
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldstr, "arg1");
generator.Emit(OpCodes.Call, ctor1);
generator.Emit(OpCodes.Ret);

这似乎是根据需要构建程序集。

使用 Reflection.Emit / Sigil 的构造函数链接

Constructor chaining with Reflection.Emit / Sigil

c#

cil

reflection.emit