C# 如何为异步等待调用创建包装器？

据我所知，没有内置（或框架扩展）支持

ConnectAsync

/

acceptsync

/

sendaync

/

ReceiveAsync

等。。如何编写异步等待机制支持的自己的包装器。例如，我的当前代码处理内联和回调上的

ReceiveAsyn

c（在

SocketAsyncEventArgs

中指定）：

诀窍是用来处理这种情况

---

我在博客上写了这件事。有关详细信息，请参阅。

您还可以编写一个定制的watiable，在这种情况下我更喜欢它。这是微软的Stephen Toub的一项技术。您可以在这里阅读更多有关此技术的信息。

这是一个值得期待的习俗：

public sealed class SocketAwaitable : INotifyCompletion
{
    private readonly static Action SENTINEL = () => { };
    internal bool m_wasCompleted;
    internal Action m_continuation;
    internal SocketAsyncEventArgs m_eventArgs;
    public SocketAwaitable(SocketAsyncEventArgs eventArgs)
    {
        if (eventArgs == null) throw new ArgumentNullException("eventArgs");
        m_eventArgs = eventArgs;
        eventArgs.Completed += delegate
        {
            var prev = m_continuation ?? Interlocked.CompareExchange(
                ref m_continuation, SENTINEL, null);
            if (prev != null) prev();
        };
    }
    internal void Reset()
    {
        m_wasCompleted = false;
        m_continuation = null;
    }
    public SocketAwaitable GetAwaiter() { return this; }
    public bool IsCompleted { get { return m_wasCompleted; } }
    public void OnCompleted(Action continuation)
    {
        if (m_continuation == SENTINEL ||
            Interlocked.CompareExchange(
                ref m_continuation, continuation, null) == SENTINEL)
        {
            Task.Run(continuation);
        }
    }
    public void GetResult()
    {
        if (m_eventArgs.SocketError != SocketError.Success)
            throw new SocketException((int)m_eventArgs.SocketError);
    }
}

要添加到socket类并使其方便的一些扩展方法：

public static class SocketExtensions
{
    public static SocketAwaitable ReceiveAsync(this Socket socket,
        SocketAwaitable awaitable)
    {
        awaitable.Reset();
        if (!socket.ReceiveAsync(awaitable.m_eventArgs))
            awaitable.m_wasCompleted = true;
        return awaitable;
    }
    public static SocketAwaitable SendAsync(this Socket socket,
        SocketAwaitable awaitable)
    {
        awaitable.Reset();
        if (!socket.SendAsync(awaitable.m_eventArgs))
            awaitable.m_wasCompleted = true;
        return awaitable;
    }
    // ... 
}

使用中：

    static async Task ReadAsync(Socket s)
    {
        // Reusable SocketAsyncEventArgs and awaitable wrapper 
        var args = new SocketAsyncEventArgs();
        args.SetBuffer(new byte[0x1000], 0, 0x1000);
        var awaitable = new SocketAwaitable(args);

        // Do processing, continually receiving from the socket 
        while (true)
        {
            await s.ReceiveAsync(awaitable);
            int bytesRead = args.BytesTransferred;
            if (bytesRead <= 0) break;

            Console.WriteLine(bytesRead);
        }
    }

静态异步任务ReadAsync（套接字）
{
//可重用的SocketAsyncEventArgs和可等待包装器
var args=new SocketAsyncEventArgs（）；
参数SetBuffer（新字节[0x1000]，0，0x1000）；
var awaitable=新的SocketAwaitable（args）；
//进行处理，不断地从插座接收数据
while（true）
{
等待s.ReceiveAsync（可等待）；
int bytesRead=args.bytesttransfered；
如果（bytesRead对于套接字内容，.NET4.5中有一个包装器。如果您使用的是.NET4，我建议您使用APM，而不是基于事件的异步模式。它更容易转换为
任务

public static class SocketExtensions
{
    public static SocketAwaitable ReceiveAsync(this Socket socket,
        SocketAwaitable awaitable)
    {
        awaitable.Reset();
        if (!socket.ReceiveAsync(awaitable.m_eventArgs))
            awaitable.m_wasCompleted = true;
        return awaitable;
    }
    public static SocketAwaitable SendAsync(this Socket socket,
        SocketAwaitable awaitable)
    {
        awaitable.Reset();
        if (!socket.SendAsync(awaitable.m_eventArgs))
            awaitable.m_wasCompleted = true;
        return awaitable;
    }
    // ... 
}

    static async Task ReadAsync(Socket s)
    {
        // Reusable SocketAsyncEventArgs and awaitable wrapper 
        var args = new SocketAsyncEventArgs();
        args.SetBuffer(new byte[0x1000], 0, 0x1000);
        var awaitable = new SocketAwaitable(args);

        // Do processing, continually receiving from the socket 
        while (true)
        {
            await s.ReceiveAsync(awaitable);
            int bytesRead = args.BytesTransferred;
            if (bytesRead <= 0) break;

            Console.WriteLine(bytesRead);
        }
    }