FromAsync BeginReceive冻结WinForm

Question

它在控制台应用程序中工作得很好，但是当我创建WinForm时，它冻结了我的表单。

我其实知道，为什么会这样：

public static Task<int> ReceiveAsync(this Socket socket, byte[] buffer, int offset, int size, SocketFlags flags = SocketFlags.None)
{
    if (socket == null) throw new Exception("Socket is null.");
        var tcs = new TaskCompletionSource<int>(socket);
        socket.BeginReceive(buffer, offset, size, flags, iar =>
        {
            var t = (TaskCompletionSource<int>)iar.AsyncState;
            var s = (Socket)t.Task.AsyncState;
            try { t.SetResult(s.EndReceive(iar)); }
            catch (Exception exc) { t.SetException(exc); }
        }, tcs);
        return tcs.Task;
    }

while ((byteRead = ReceiveAsync(socket, buffer, 0, buffer.Length, SocketFlags.None).Result) > 0)
{
   lock (buffer)
   {
       try
       {
          byte[] dBuffer = decompressor.Decompress(buffer);
          lock (dBuffer)
          {
              string receivedData = Encoding.UTF8.GetString(dBuffer);
              OnRead(receivedData, byteRead);
          }
       }
       catch (Exception ex)
       {
          Client.Base.Log.Save(ex);
          socket.Shutdown(SocketShutdown.Both);
       }
   }
}

我认为，在分离线程中启动ReceiveAsync-Task方法不是一个好主意。

我可以使用没有while循环的异步方法(BeginXXX，EndXXX)的FormAsync吗？

提前感谢！

Answer 1

看起来你需要在单独的线程中调用你的第二个代码片段。否则，第二个代码片段只会强制第一个代码片段的异步调用同步工作(这就是WindowsForms应用程序挂起的原因--只需调用您在单独线程中发布的整个第二部分代码，它就可以正常工作)。

编辑

为了避免应用程序挂起，可以稍微更改您使用的函数的定义，如下所示：

    // Is not changed
    public static Task<int> ReceiveAsync(this Socket socket, byte[] buffer, int offset, int size, SocketFlags flags = SocketFlags.None)
    {

        if (socket == null) throw new Exception("Socket is null.");

        var tcs = new TaskCompletionSource<int>(socket);
        socket.BeginReceive(buffer, offset, size, flags, iar =>
        {
            var t = (TaskCompletionSource<int>)iar.AsyncState;
            var s = (Socket)t.Task.AsyncState;
            try { t.SetResult(s.EndReceive(iar)); }
            catch (Exception exc) { t.SetException(exc); }
        }, tcs);
        return tcs.Task;
    }

    // Moved to new function
    public void PerformRead()
    {
        while ((byteRead = ReceiveAsync(socket, buffer, 0, buffer.Length, SocketFlags.None).Result) > 0)
        {
           lock (buffer)
           {
               try
               {
                  byte[] dBuffer = decompressor.Decompress(buffer);
                  lock (dBuffer)
                  {
                      string receivedData = Encoding.UTF8.GetString(dBuffer);
                      OnRead(receivedData, byteRead);
                  }
               }
               catch (Exception ex)
               {
                  Client.Base.Log.Save(ex);
                  socket.Shutdown(SocketShutdown.Both);
               }
           }
        }
    }

然后，当您通过以下方式调用读取套接字时，您的应用程序将顺利工作(没有延迟)：

// Invokes reading of socket in separate thread
Thread readSocketThread = new Thread(this.PerformRead);
readSocketThread.Start();

注意：您必须以某种方式(例如，通过某些字段或属性，或者直接从读取socket的线程访问表单字段)将读取到windows窗体控件的数据传送给windows窗体控件。