"Exception has been thrown by the target of an invocation." 使用两个参数实现函数时出现问题

Question

我正在尝试为动态生成的 class/method 实现接口。对于带有一个参数的方法（在代码中注释），该实现是可以的。但是当方法有两个或更多参数时，它会抛出 "Exception has been thrown by the target of an invocation"。无法弄清楚两个参数有什么问题？任何帮助，将不胜感激。下面是我的代码：

using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Linq;
    using System.Linq.Expressions;
    using System.Net.Http;
    using System.Reflection;
    using System.Reflection.Emit;
    using System.Security.Permissions;
    using System.Text;
    using System.Threading;
    using System.Threading.Tasks;
    using System.Web.Http;
    using System.Web.Http.Controllers;

    namespace ConsoleApplication7
    {
        public class Foo
        {
            public string Bar(string m)
            {
                return m;
            }

        }
        public interface IFoo
        {
            string Barz(int i, int s);
            //string Barz(int i);// works good
        }

        public class Program
        {

            public string my(int w, int s)
            {
                return (s + w).ToString();
            }
            [PermissionSetAttribute(SecurityAction.Demand, Name = "FullTrust")]
            public void TestMethod()
            {

                var ab = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName("TestAssembly"), AssemblyBuilderAccess.RunAndSave);

                var mb = ab.DefineDynamicModule("Test");
                var tb = mb.DefineType("Foo", typeof(Foo).Attributes, typeof(Foo));
                tb.AddInterfaceImplementation(typeof(IFoo));
                foreach (var imethod in typeof(IFoo).GetMethods())
                {
                    var method =
                      tb.DefineMethod
                      (
                        "@@" + imethod.Name,
                        MethodAttributes.Private | MethodAttributes.Static,
                        CallingConventions.Standard,
                        imethod.ReturnType,
                        imethod.GetParameters().Select(n => n.ParameterType).ToArray()
                      );

                    var thisParameter = Expression.Parameter(typeof(IFoo), "this");
                    var param = new ParameterExpression[] { Expression.Parameter(typeof(int)), Expression.Parameter(typeof(int)) };

                    var bodyExpression =
                      Expression.Lambda<Func<int,int, string>>(
                      Expression.Call(
                         Expression.New(typeof(Program)),
                         typeof(Program).GetMethod("my", new Type[] { typeof(int), typeof(int) }), param

                         ), param);
                    //var y = bodyExpression.Compile();//compiles good
                    //  var p = y.Invoke(200, "");//invocation is ok
                    bodyExpression.CompileToMethod(method);
                    var mp = imethod.GetParameters().Select(r => r.ParameterType).ToArray();
                    var stub =
                      tb.DefineMethod(imethod.Name, MethodAttributes.Public | MethodAttributes.Virtual, CallingConventions.Standard,
                       imethod.ReturnType, mp);
                    var il = stub.GetILGenerator();
                    il.Emit(OpCodes.Ldarg_0);
                    il.EmitCall(OpCodes.Call, method, null);
                    il.Emit(OpCodes.Ret);
                    tb.DefineMethodOverride(stub, imethod);
                }
                var type = tb.CreateType();
                ab.Save("test.dll");
                var obj = CreateAndInvoke(type, null, "Barz", null);

                Console.ReadLine();

            }
            public static object CreateAndInvoke(Type typeName, object[] constructorArgs, string methodName, object[] methodArgs)
            {
                Type type = typeName;
                object instance = Activator.CreateInstance(type);
                object[] a = new object[] { 900 ,0};
                MethodInfo method = type.GetMethod(methodName);
                return method.Invoke(instance, a);//issue over here
            }
            [PermissionSetAttribute(SecurityAction.Demand, Name = "FullTrust")]
            public static void Main(string[] args)
            {
                new Program().TestMethod(); 

            }


        }
    }

Answer 1

Unable to figure out what is wrong with two args? Any help would be appreciated.

代码生成的代码没有任何意义。它被编写为为任意方法调用生成一个存根，然后将单个参数传递给该方法，而不管该方法的参数。那是完全错误的；该代码仅适用于一个参数的方法。

运行时将在验证或 jitting 期间识别该问题，并给出无效程序异常，而不是运行和未对齐堆栈。

"Exception has been thrown by the target of an invocation." 使用两个参数实现函数时出现问题

"Exception has been thrown by the target of an invocation." issue while implementing function with two params

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