"A socket operation failed because the destination host was down" 将电脑连接到移动设备时

Question

我的项目是使用 32feet.net 库连接电脑和移动设备。

到目前为止，我的解决方案是执行以下步骤：

正在扫描区域中的设备。
正在与所选设备配对。
请求与移动设备配对，当没问题时出现此错误：

"A socket operation failed because the destination host was down" 而且我不知道为什么以及如何克服这个问题。任何对此问题的帮助将不胜感激。

我的解决方案是：

namespace Bluetooth
{

public partial class Form1 : Form
{
    List<string> items;
    public Form1()
    {
        items = new List<string>();

        InitializeComponent();
    }

    private void Connect_Click(object sender, EventArgs e)
    {
        if(ServerStarted )
        {
            updateUI("Server Already Started");
            return;
        }
        if(rbClient.Checked)
        {
            //ConnectAsClient();
            StartScan();
        }
        else
        {
            ConnectAsServer();
        }
    }
    private void StartScan()
    {
        listBox.DataSource = null;
        listBox.Items.Clear();
        items.Clear();
        Thread bluethoothscanthread = new Thread(new ThreadStart(scan));
        bluethoothscanthread.Start();
    }
    BluetoothDeviceInfo[] devices;
    private void scan()
    {
        updateUI("Starting Scan ...");
        BluetoothClient client = new BluetoothClient();
        devices = client.DiscoverDevicesInRange();
        updateUI("Scan Completed......");
        updateUI(devices.Length.ToString() + "devices discovered");
        foreach(BluetoothDeviceInfo d in devices)
        {
            items.Add(d.DeviceName);
        }

        UpdateDeviceList();
    }

    private void ConnectAsServer()
    {
        Thread BluethoothServerThread = new Thread(new ThreadStart(ServerConnectThread));
        BluethoothServerThread.Start();
    }

    private void ConnectAsClient()
    {
        throw new NotImplementedException();
    }

    Guid mUUID = new Guid("00001101-0000-1000-8000-00805F9B34FB");  

    bool ServerStarted = false;
    public void ServerConnectThread()
    {
        ServerStarted = true;
        updateUI("Server Started , Waiting For Clients ");
       BluetoothListener bluelistner = new BluetoothListener(mUUID);
       bluelistner.Start();
       BluetoothClient conn = bluelistner.AcceptBluetoothClient();
       updateUI("Client has connected");
       Stream mstream = conn.GetStream();

        while(true)
        {
            // handle server connection
            try
            {
                byte[] Received = new byte[1024];
                mstream.Read(Received, 0, Received.Length);
                updateUI("Received : " + Encoding.ASCII.GetString(Received));
                byte[] Sent = Encoding.ASCII.GetBytes("Hello World ");
                mstream.Write(Sent, 0, Sent.Length);
            }
            catch(IOException exception)
            {
                updateUI("Client has disconnected !!! ");
            }
        }
    }
    private void updateUI(string message)
    {
        Func<int> del = delegate ()
            {
                tbOutput.AppendText(message + System.Environment.NewLine);
                return 0 ;
            };
            Invoke(del);       
    }

    private void UpdateDeviceList()
    {
        Func<int> del = delegate ()
        {
            listBox.DataSource = items;
            return 0;
        };
        Invoke(del);
    }

    BluetoothDeviceInfo deviceinfo;
    private void listBox_DoubleClick(object sender, EventArgs e)
    {
        deviceinfo = devices.ElementAt(listBox.SelectedIndex);
        updateUI(deviceinfo.DeviceName + "Was Selected , attempting connect");
       if( pairDevice())
       {
           updateUI("Device Paired.....");
           updateUI("Starting Connect Thread");
           Thread bluethoothClientThread = new Thread(new ThreadStart(ClientconnectThread));
           bluethoothClientThread.Start();
       }
       else
       {
           updateUI("Pair Failed");
       }
    }

    private void ClientconnectThread()
    {
        BluetoothClient client = new BluetoothClient();
        updateUI("Attempting Connect");
        client.BeginConnect(deviceinfo.DeviceAddress, mUUID, this.BluetoothClientConnectCallback, client);
    }
    void BluetoothClientConnectCallback(IAsyncResult result)
    {
        BluetoothClient client = (BluetoothClient)result.AsyncState;

       BluetoothEndPoint bep = new BluetoothEndPoint(deviceinfo.DeviceAddress, BluetoothService.AvctpProtocol);
       BluetoothClient cli = new BluetoothClient();

       client.Connect(bep); // the exception throw in this line //
       Stream stream = cli.GetStream();
       stream.ReadTimeout = 10000;
       //Stream peerStream = cli.GetStream();

        // client.Connect(BluetoothAddress.Parse(items(0)), mUUID);


        //client.EndConnect(result);
        //while(true)
        //{
        //    while (!ready) ;
        //    stream.Write(message, 0, message.Length);
        //}

        //streaming(result);
        if(result.IsCompleted)
        {
           // client.EndConnect(result);
           // Stream stream = client.GetStream();
           // stream.ReadTimeout = 1000;

            updateUI("Ya rabbbbb");


            //while (!ready) ;
            //stream.Write(message, 0, message.Length);
        }
    }
    void streaming (IAsyncResult result)
    {
        BluetoothListener listn = new BluetoothListener(mUUID);
        listn.Start();
        BluetoothClient conn = listn.AcceptBluetoothClient();
        Stream peerstream = conn.GetStream();
        bool rightconn = peerstream.CanRead;
        if(rightconn)
        {
            updateUI("Now you can streaming");
        }
        else
        {
            updateUI("Not Yet");
        }
    }

    string mypin = "1234";
    private bool pairDevice()
    {
        if(!deviceinfo.Authenticated)
        {
            if (!BluetoothSecurity.PairRequest(deviceinfo.DeviceAddress, mypin))
            {
                return false;
            }
        }
        return true;
    }

    bool ready = false;
    byte[] message;
    private void tbText_KeyPress(object sender, KeyPressEventArgs e)
    {
        if(e.KeyChar == 13)
        {
            message = Encoding.ASCII.GetBytes(tbText.Text);
            ready = true;
            tbText.Clear();
        }
    }
}

} // End of namespace

Answer 1

我想我跟你做了同样的例子，当然我遇到了同样的问题。

在 "private void ClientconnectThread()" 功能之前，我的其余代码与您的相同，这是我的代码；

private void ClientConnectThread()
    {
        BluetoothClient client = new BluetoothClient();
        updateUI("attempting connect");
        //client.BeginConnect(deviceInfo.DeviceAddress, mUUID, this.BluetoothClientConnectCallback, client);
        BluetoothAddress addressSeleccionado = deviceInfo.DeviceAddress;
        Guid mUUID = new Guid("00001101-0000-1000-8000-00805F9B34FB");
        BluetoothEndPoint ep = new BluetoothEndPoint(addressSeleccionado, mUUID);
        client.Connect(ep);
        updateUI("connected");
        Stream stream = client.GetStream();
        while (true)
        {
            byte[] received = new byte[1024];
            stream.Read(received, 0, received.Length);
            updateUI("received: ");
            for (int i = 0; i < 15; i++)
            {
                updateUI(received[i].ToString());
            }
            if (ready)
            {
                ready = false;
                stream.Write(message, 0, message.Length);
            }
        }
    }

使用此代码，我可以连接远程设备并实现基本的 send/receive 数据通信。为了我在互联网上的搜索，"if this code does not fit for you"，你可能会认为 32feet 与你的蓝牙驱动程序不兼容。（顺便说一句，我的电脑 OS 是 64 位 Win7，我使用我电脑的内置 BT 设备）

此致。

"A socket operation failed because the destination host was down" 将电脑连接到移动设备时

"A socket operation failed because the destination host was down" when connecting pc to mobie device

c#

sockets

networking

bluetooth

32feet