C#中关于异步的三种写法

时间:2021-10-04 03:46:53

IAsyncResult ar = d1.BeginInvoke(1, 3000, null, null);

while (!ar.IsCompleted)

class Program

{

static int TakesAWhile(int data, int ms)

{

Console.WriteLine("TakesAWhile started");

Thread.Sleep(ms);

Console.WriteLine("TakesAWhile completed");

return ++data;

}

public delegate int TakesAWhileDelegate(int data, int ms);

static void Main(string[] args)

{

TakesAWhileDelegate d1 = TakesAWhile;

IAsyncResult ar = d1.BeginInvoke(1, 3000, null, null);

while (!ar.IsCompleted)

{

// doing something else

Console.Write(".");

Thread.Sleep(50);

}

int result = d1.EndInvoke(ar);

Console.WriteLine("result: {0}", result);

Console.ReadLine();

}

}

2 等待句柄 

class Program

{

static int TakesAWhile(int data, int ms)

{

Console.WriteLine("TakesAWhile started");

Thread.Sleep(ms);

Console.WriteLine("TakesAWhile completed");

return ++data;

}

public delegate int TakesAWhileDelegate(int data, int ms);

static void Main(string[] args)

{

TakesAWhileDelegate d1 = TakesAWhile;

IAsyncResult ar = d1.BeginInvoke(1, 3000, null, null);

int i = 0;

while (true)

{

Console.Write(i++);

Console.Write(".");

if (ar.AsyncWaitHandle.WaitOne(50, true))

{

Console.WriteLine("Can get the result now");

break;

}

}

int result = d1.EndInvoke(ar);

Console.WriteLine("result: {0}", result);

}

}

3 回调 pdf533  p509

class Program

{

static int TakesAWhile(int data, int ms)

{

Console.WriteLine("TakesAWhile started");

Thread.Sleep(ms);

Console.WriteLine("TakesAWhile completed");

return ++data;

}

public delegate int TakesAWhileDelegate(int data, int ms);

static void Main(string[] args)

{

TakesAWhileDelegate d1 = TakesAWhile;

IAsyncResult ar = d1.BeginInvoke(1, 3000, TakesAWhileCompleted, d1);

for (int i = 0; i < 100; i++)

{

Console.Write(".");

Thread.Sleep(50);

}

Console.ReadLine();

}

static void TakesAWhileCompleted(IAsyncResult ar)

{

if (ar == null) throw new ArgumentNullException("ar");

TakesAWhileDelegate d1 = ar.AsyncState as TakesAWhileDelegate;

Trace.Assert(d1 != null, "Invalid object type");

int result = d1.EndInvoke(ar);

Console.WriteLine("result: {0}", result);

}

}

通过lambda表达式来实现:

static int TakesAWhile(int data, int ms)

{

Console.WriteLine("TakesAWhile started");

Thread.Sleep(ms);

Console.WriteLine("TakesAWhile completed");

return ++data;

}

public delegate int TakesAWhileDelegate(int data, int ms);

static void Main(string[] args)

{

TakesAWhileDelegate d1 = TakesAWhile;

d1.BeginInvoke(1, 3000,

ar =>

{

int result = d1.EndInvoke(ar);

Console.WriteLine("result: {0}", result);

},

null);

for (int i = 0; i < 100; i++)

{

Console.Write(".");

Thread.Sleep(50);

}

Console.ReadLine();

}

var completed = new AutoResetEvent(false);

var args = new SocketAsyncEventArgs();

args.RemoteEndPoint = endpoint;

args.Completed += OnConnectCompleted;

args.UserToken = completed;

socket.ConnectAsync(args);

if (!completed.WaitOne(timeout) || !socket.Connected)

{

using (socket)

{

throw new TimeoutException("Could not connect to " + endpoint);