C#中的委托Delegate

public delegate void HandlerDelegate(string message);

HandlerDelegate myDelegate;//声明委托变量

//myDelegate = new HandlerDelegate(Method1);//可以为静态方法或者实例方法。
//或者直接myDelegate = Method1;

public void Method1(string mgs)
{
    Console.WriteLine(mgs);
}

myDelegate = delegate (string message)//实例化委托(带函数引用)
{
    Console.WriteLine(message);
};

myDelegate = (message) => { Console.WriteLine(message); };

myDelegate("Hello World");//同步调用

public delegate void HandlerDelegate(string message);

void Main()
{
    HandlerDelegate myDelegate;//声明委托变量
    myDelegate = (message) => { Console.WriteLine("a " + message); };
    myDelegate += (message) => { Console.WriteLine("b " + message); };
    myDelegate += (message) => { Console.WriteLine("c " + message); };
    myDelegate("Hello World");//多个方法依次调用
    Console.WriteLine(myDelegate.GetInvocationList().GetLength(0));//3
}

public delegate void HandlerDelegate(string message);

//客户端
void Main()
{
    HandlerDelegate myDelegate;//声明委托变量
    myDelegate = (message) =>
    {
        Console.WriteLine("计算结果为：" + message);
    };

    MyClass myClass = new MyClass();
    myClass.MethodWithCallback(2, myDelegate);
}


//作为服务端，计算完成后，将结果返回给客户端
public class MyClass
{
    public void MethodWithCallback(int a, HandlerDelegate callback)
    {
        a = a + 1;
        callback("result:" + a.ToString());//执行委托
    }
}

public delegate int AddHandler(int a, int b);

void Main()
{
    AddHandler handler = (a, b) =>
    {
        return (a + b);
    };
    //int result = handler(2, 3);
    int result = handler.Invoke(2, 3);//此句调用的方法执行完毕后才执行往下的语句。
    Console.Write(result);//5
}

public delegate int AddHandler(int a, int b);

void Main()
{
    AddHandler handler = (a, b) =>
    {
        return (a + b);
    };

    IAsyncResult ar = handler.BeginInvoke(2, 3, null, null);

    //while (!ar.IsCompleted)
    //{
    //     Console.WriteLine("Do Sth.");//在委托的工作未完成之前，主线程可做其他事情。
    //}
    //或
    while (!ar.AsyncWaitHandle.WaitOne(0, false))
    {
        Console.WriteLine("Do Sth.");
    }

    int result = handler.EndInvoke(ar);
    Console.Write(result);//5
}

public delegate int AddHandler(int a, int b);

void Main()
{
    AddHandler handler = (a, b) =>
    {
        return (a + b);
    };

    IAsyncResult ar = handler.BeginInvoke(2, 3, new AsyncCallback(AddComplete), null);
    Console.WriteLine("Do Sth.");//异步调用完成时调用此方法。

}
public void AddComplete(IAsyncResult ar)
{
    AddHandler handler = ((AsyncResult)ar).AsyncDelegate as AddHandler;
    Console.WriteLine(handler.EndInvoke(ar));
}