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我已经阅读了有关 SignalR 的几篇文章，并考虑了一个有趣的测试项目，我可以创建一个 Web 应用程序来轮询我的 onkyo 接收器的状态并在浏览器中显示结果。对于初始测试，我通过在 Application_Start 中使用以下代码成功地将服务器上的当前时间发送回客户端：

ThreadPool.QueueUserWorkItem(_ =>
{               
    dynamic clients = Hub.GetClients<KudzuHub>();
    while (true)
    {                
        clients.addMessage(DateTime.Now.ToString());

        Thread.Sleep(1000);
    }
});

在客户端javascript中，我有以下代码：

// Proxy created on the fly
var kHub = $.connection.kudzuHub;

// Declare a function on the hub so that the server can invoke it
kHub.addMessage = function (message) {
    console.log('message added');
    $('#messages').append('<li>' + message + '</li>');
};

// start the connection
$.connection.hub.start();

所以所有这些都很好。每一秒，我都会得到一个包含当前服务器日期和时间的新列表项。

现在，当我添加此代码以从 Onkyo 接收器读取数据时，它会中断：（仍在 Application_Start 中）

ThreadPool.QueueUserWorkItem(_ =>
{  
    dynamic clients = Hub.GetClients<KudzuHub>();
    try
    {
        while (true)
        {
            string host = ConfigurationManager.AppSettings["receiverIP"].ToString();
            int port = Convert.ToInt32(ConfigurationManager.AppSettings["receiverPort"]);

            TcpClient tcpClient = new TcpClient(host, port);

            NetworkStream clientSockStream = tcpClient.GetStream();

            byte[] bytes = new byte[tcpClient.ReceiveBufferSize];
            clientSockStream.Read(bytes, 0, (int)tcpClient.ReceiveBufferSize);

            tcpClient.Close();

            clients.addMessage(System.Text.Encoding.ASCII.GetString(bytes));
            Thread.Sleep(50);
        }
    }
    catch (SocketException ex)
    {
        // do something to handle the error
    }

});

我设置了一个断点并单步执行了代码。它到达这条线，然后返回。

clientSockStream.Read(bytes, 0, (int)tcpClient.ReceiveBufferSize);

它永远不会完成将消息发送到客户端的其余代码。我究竟做错了什么？

谢谢。

4

1 回答 1

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我将对您的循环进行一些结构更改，以允许接收器有时间响应，消除每 50 毫秒检索一次配置的开销，并清理开放的网络流：

ThreadPool.QueueUserWorkItem(_ =>
{  
    dynamic clients = Hub.GetClients<KudzuHub>();
    TcpClient tcpClient = null;
    NetworkStream clientSockStream = null;

    try
    {
        string host = ConfigurationManager.AppSettings["receiverIP"].ToString();
        int port = Convert.ToInt32(ConfigurationManager.AppSettings["receiverPort"]);

        while (true)
        {
            if (tcpClient == null) {
              tcpClient = new TcpClient(host, port);
              clientSockStream = tcpClient.GetStream();
            }

            if (clientSockStream.CanRead) {
                byte[] bytes = new byte[tcpClient.ReceiveBufferSize];
                try {
                   clientSockStream.Read(bytes, 0, (int)tcpClient.ReceiveBufferSize);
                } catch (Exception ex) {
                  // Add some debug code here to examine the exception that is thrown
                }

                tcpClient.Close();
                // Closing the client does not automatically close the stream
                clientSockStream.Close();

                tcpClient = null;
                clientSockStream = null;

                clients.addMessage(System.Text.Encoding.ASCII.GetString(bytes));
            }
            Thread.Sleep(50);
        }
    }
    catch (SocketException ex)
    {
        // do something to handle the error
    } finally {
       if (tcpClient != null) {
         tcpClient.Close();
         clientSockStream.Close();
       }
    } 

});
于 2011-12-04T04:04:07.130 回答