5

我是反射.emit 的新手，一直在尝试生成以下 c# 代码：

public class RepositoryWrapper
{
    public void CallRepositoryMethod(IAddressRepository repository, Address address)
    {
        repository.NODE_I_NodeExtendedDetails_Address3(address.NodeId);
    }
}

这是它的 il 表示：

    IL_0000: nop
    IL_0001: ldarg.1
    IL_0002: ldarg.2
    IL_0003: callvirt instance int32 ReflectionServices.Node::get_NodeId()
    IL_0008: callvirt instance void ReflectionServices.IAddressRepository::NODE_I_NodeExtendedDetails_Address3(int32)
    IL_000d: nop
    IL_000e: ret

这是我用来创建它的代码：

 internal static void Generate(this System.Reflection.Emit.ILGenerator @this, Type target,string method,Type instance)
        {

        var methodToCall = target.GetMethod(method);
        var methodParams = methodToCall.GetParameters();
        var instanceProperties = instance.GetProperties(BindingFlags.Public | BindingFlags.Instance);

        var orderedProperties = (from mp in methodParams
                              join p in instanceProperties
                              on mp.Name.ToLower() equals p.Name.ToLower()
                              select p).ToArray();

        //add properties to the string builder

        //load the object reference onto the stack sothat we can access its methods
        @this.Emit(OpCodes.Nop);
        @this.Emit(OpCodes.Ldarg_1);
        @this.Emit(OpCodes.Ldarg_2);

            var property = orderedProperties.FirstOrDefault(x => x.Name == "NodeId");
            if (property != null)
            {
                var getMethod = property.GetGetMethod();
                @this.Emit(getMethod.IsVirtual ? OpCodes.Callvirt : OpCodes.Call, getMethod);

            }


        //call method 
            @this.Emit(methodToCall.IsVirtual ? OpCodes.Callvirt : OpCodes.Call, methodToCall);
            @this.Emit(OpCodes.Nop);
        //return from function
        @this.Emit(OpCodes.Ret);
        }

这是我得到的错误：

System.InvalidProgramException: Common Language Runtime detected an invalid program.
Result StackTrace:  
at ReflectionServices.Repository.NODE_I_NodeExtendedDetails3_Address40807399(Repository      target, Address )

这是生成的 il：

nop
ldarg.1
ldarg.2
call instance int32 ReflectionServices.Node::get_NodeId()
callvirt instance void            
ReflectionServices.Repository::
                               NODE_I_NodeExtendedDetails3_Address(int32)
nop

ret

任何人都可以看到我被卡住的问题是什么？

谢谢

这是我要求的dll和方法：

 public sealed class ReflectionEmitWithDebuggingMethodGenerator
{
    private AssemblyBuilder Assembly { get; set; }
    private ModuleBuilder Module { get; set; }
    private AssemblyName Name { get; set; }

    public ReflectionEmitWithDebuggingMethodGenerator()
        : base()
    {
        this.Name = new AssemblyName() { Name = Guid.NewGuid().ToString("N") };
        this.Assembly = AppDomain.CurrentDomain.DefineDynamicAssembly(
            this.Name, AssemblyBuilderAccess.RunAndSave,@"C:\Users\darren\Documents\Visual Studio 2012\Projects\UnityInjection");
        this.AddDebuggingAttribute(this.Assembly);
        this.Module = this.Assembly.DefineDynamicModule(this.Name.Name + ".dll", true);
    }
   public Action<TObject, TInstance> Generate<TObject, TInstance>(Type target, string methodN, Type instanceType)
    {
        var type = this.Module.DefineType(target.Namespace + "." + target.Name);
        var methodName = methodN + target.GetHashCode().ToString();
        var method = type.DefineMethod(methodName, MethodAttributes.Static | MethodAttributes.Public, typeof(void), new Type[] { target, instanceType });
        method.DefineParameter(1, ParameterAttributes.In, "target");
        method.DefineParameter(2, ParameterAttributes.In, "instance");

        ILGenerator.Generate(method.GetILGenerator(), target,methodN,instanceType);

        var createdType = type.CreateType();

        var createdMethod = createdType.GetMethod(methodName);
        return (Action<TObject, TInstance>)Delegate.CreateDelegate(typeof(Action<TObject, TInstance>), createdMethod);
    }


}
4

1 回答 1

3

比较编译和发出的输出，只有一个区别：

编译：

callvirt instance int32 ReflectionServices.Node::get_NodeId()

发射：

call instance int32 ReflectionServices.Node::get_NodeId()

您调用的类型int32 get_NodeId()是ReflectionServices.Node，但是您传递给您尝试复制的方法的对象的类型是Address. 这使我相信ReflectionServices.Node必须虚拟调用定义的属性访问器，可能是因为它继承自另一个在ReflectionServices.Node实现该属性之前声明该属性的类（或实现一个接口）。

当您发出那行代码时，只需虚拟调用它：

@this.Emit(OpCodes.Callvirt, getMethod);

编辑：根据进一步提供的代码，这是真正的解决方案。

因此，您对如何实现接口的基本原理有疑问：

var method = type.DefineMethod(methodName, MethodAttributes.Static | Method...
//                                                          ^^^^^^

接口方法不是静态的；他们是实例成员。因此，您首先需要MethodAttributes.Static在创建MethodBuilder.

其次，当您返回此函数时，您将必须包含一个目标对象，它是调用该方法的实例。为此，您可以使用Activator.CreateInstance调用默认生成的构造函数并为您提供一个实例化对象以用作目标。用这些行替换方法的最后一行Generate来实现这一点。

var activatedObject = Activator.CreateInstance(type);

return (Action<TObject, TInstance>)Delegate.CreateDelegate(
    typeof(Action<TObject, TInstance>), activatedObject, createdMethod);
于 2013-06-05T22:06:36.583 回答