使用反射注册Action<string>事件的求助

using System;

namespace RefTest
{
    public class Test
    {
        public event Action<string> OnMessage;

        public void WriteString()
        {
            Console.WriteLine("Write String");
            OnMessage?.Invoke("ActionMessage");
        }
    }
}

using System;
using System.Diagnostics;
using System.Reflection;

namespace ConsoleAppFixed
{
    class Program
    {
        static void Main(string[] args)
        {
            //反射加载
            Assembly assembly = Assembly.LoadFrom("RefTest.dll");      //加载程序集
            Type typeClass = assembly.GetType("RefTest.Test");             //获取类型（命名空间.类名）
            object obj = Activator.CreateInstance(typeClass);                  //实例化
            MethodInfo method = typeClass.GetMethod("WriteString"); //查找方法
            method.Invoke(obj, null);                                                      //方法调用


            //注册事件
            var t = typeof(Action<string>);
            Delegate mDelegate = Delegate.CreateDelegate(t, obj, "OnMessage");

            //这里不会注册了

            Console.ReadKey();
        }

        public static void Recieve()
        {
        }
    }
}