How to pass Struct parameter when a Dynamic Method Invoke in C#?

Question

I have trouble with pass struct parameter in dynamic method. Here is my code:

public class Program
{
    static void Main(string[] args)
    {
        var DynamicAssembly = new AssemblyName();
        DynamicAssembly.Name = "DynamicTypes";
        AssemblyBuilder ab = AssemblyBuilder.DefineDynamicAssembly(DynamicAssembly, AssemblyBuilderAccess.Run);
        ModuleBuilder mb = ab.DefineDynamicModule(DynamicAssembly.Name);
        TypeBuilder tb = mb.DefineType("Handler", TypeAttributes.Class | TypeAttributes.Public);
        MethodBuilder handler = tb.DefineMethod($"DynamicHandler",
            MethodAttributes.Public | MethodAttributes.Static,
           typeof(void),
           new Type[] { typeof(MyClass), typeof(MyStruct) });
        var ProcessMethod = typeof(Program).GetMethod(nameof(Process));
        ILGenerator il = handler.GetILGenerator();
        il.Emit(OpCodes.Nop);
        il.Emit(OpCodes.Ldarg_0);
        il.Emit(OpCodes.Ldarg_1);
        il.EmitCall(OpCodes.Call, ProcessMethod, null);
        il.Emit(OpCodes.Nop);
        il.Emit(OpCodes.Ret);
        var DynamicType = tb.CreateType();
        MethodInfo methodInfo = DynamicType.GetMethod("DynamicHandler");
        int i = 100;
        while (true)
        {
            i++;
            MyClass a = new MyClass()
            {
                a = i,
            };
            MyStruct b = new MyStruct()
            {
                b = i,
            };
            methodInfo.Invoke(null, new object[] { a, b });
            Thread.Sleep(3000);
        }
    }
    public static void Process(object arg1, object arg2)
    {
        Console.WriteLine($"arg1:{arg1} arg2:{arg2}");
    }
}
public struct MyStruct
{
    public int a;
    public int b;
}
public class MyClass
{
    public int a;
    public int b;
}

When I run my code to Process method parameter arg2 found 'FatalExecutionEngineError' cannot read memory.

But if I change my second parameter to MyStruct like

    public static void Process(object arg1,MyStruct arg2)
    {
        Console.WriteLine($"arg1:{arg1} arg2:{arg2}");
    }

It works normal,but It's not what I want.

I think my IL code is not correct,but I don't known where is it.

Answer 1

You have to call OpCodes.Box on MyStruct in order to pass it as object as a parameter to a method.

You also do not need to call OpCodes.Nopeither. So basically what your code should be like is→

il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Box, typeof(MyStruct));
//Rest is the same