create a new method with a user-defined name. Reflection C#

Question

I want to create a method on RunTime. I want the user to enter a string and the method's name will be DynamicallyDefonedMethod_#### (ends with the user string).

i want the same string to be embeded in the method's body: It will call StaticallyDefinedMethod (####, a, b)

Something like:

public MyClass1 DynamicallyDefonedMethod_#### (int a, int b)
{
return  StaticallyDefinedMethod (####, a, b)
}

The idea is that the user will create a new method on runtime and invoke it afterward (with a, b parameters).

i googled C# reflection but found no easy way of doing that. Does someone knows how to do it simply ?

Regards,

Answer 1

As already noted (comments), the easier approach is just to use a lambda:

Func<int,int,Whatever> func = (a,b) => StaticallyDefinedMethod(s,a,b);

but you can also use meta-programming for this (below). Here you control the method name, and have more flexibility (not that you need it here). But note that this doesn't really add a method to the type - the dynamic method is separate and disconnected. You can't really add members to types at runtime.

using System;
using System.Reflection.Emit;
public class MyClass1  {
    static void Main()
    {
        var foo = CreateMethod("Foo");
        string s = foo(123, 456);
        Console.WriteLine(s);
    }
    static Func<int,int,string> CreateMethod(string s)
    {
        var method = new DynamicMethod("DynamicallyDefonedMethod_" + s,
            typeof(string),
            new Type[] { typeof(int), typeof(int) });
        var il = method.GetILGenerator();
        il.Emit(OpCodes.Ldstr, s);
        il.Emit(OpCodes.Ldarg_0);
        il.Emit(OpCodes.Ldarg_1);
        il.EmitCall(OpCodes.Call, typeof(MyClass1).GetMethod("StaticallyDefinedMethod"), null);
        il.Emit(OpCodes.Ret);
        return (Func<int,int,string>)method.CreateDelegate(typeof(Func<int, int, string>));
    }
    public static string StaticallyDefinedMethod(string s, int a, int b)
    {
        return s + "; " + a + "/" + b;
    }
}

A final thought here might be to use dynamic, but it is very hard to choose names at runtime with dynamic.