使用反射将委托连接到事件？

Question

我有 2 个 DLL，A.dll 包含：

namespace Alphabet
{
    public delegate void TestHandler();

    public class A  
    {
        private void DoTest()
        {
            Type type = Assembly.LoadFile("B.dll").GetType("Alphabet.B");                       

            Object o = Activator.CreateInstance(type);

            string ret = type.InvokeMember("Hello", BindingFlags.InvokeMethod | BindingFlags.Default, null, o, null);
        }
    }
}

B.dll 包含

namespace Alphabet
{   
    public class B
    {
        public event TestHandler Test();

        public string Hello()
        {
            if (null != Test) Test();
            return "Hello";
        }
    }
}

我正在使用 InvokeMember 从 B.dll 获取结果，我还希望 B.dll Test()< /code> 返回结果之前。那么，如何通过反射将delegate挂接到B.dll中的event呢？

任何帮助将不胜感激！

Answer 1

使用 typeof(B).GetEvent("Test") 获取事件，然后使用 EventInfo.AddEventHandler 将其挂钩。示例代码：

using System;
using System.Reflection;

public delegate void TestHandler();

public class A  
{
    static void Main()
    {
        // This test does everything in the same assembly just
        // for simplicity
        Type type = typeof(B);
        Object o = Activator.CreateInstance(type);

        TestHandler handler = Foo;
        type.GetEvent("Test").AddEventHandler(o, handler);
        type.InvokeMember("Hello",
                          BindingFlags.Instance | 
                          BindingFlags.Public |
                          BindingFlags.InvokeMethod,
                          null, o, null);
    }

    private static void Foo()
    {
        Console.WriteLine("In Foo!");
    }
}

public class B
{
    public event TestHandler Test;

    public string Hello()
    {
        TestHandler handler = Test;
        if (handler != null)
        {
            handler();
        }
        return "Hello";
    }
}