UWP RfComm - StreamSocketListener.BindServiceNameAsync 抛出异常

Question

我正在尝试创建一个侦听蓝牙串行端口连接的 UWP 应用程序。当我在应用程序中设置侦听器时（通过单击按钮），我在以下行遇到异常：

await socketListener.BindServiceNameAsync( 
      rfcommProvider.ServiceId.ToString(),
      SocketProtectionLevel.BluetoothEncryptionAllowNullAuthentication);`

异常信息是： System.ArgumentException: '参数不正确。 'protectionLevel': IP StreamSocketListeners 只允许普通套接字。'

代码如下：

private async void btnBluetoothServerClick(object sender, RoutedEventArgs e)
{
   var rfcommProvider = 
   await RfcommServiceProvider.CreateAsync(RfcommServiceId.SerialPort);

   var socketListener = new StreamSocketListener();

   socketListener.ConnectionReceived += OnConnectionReceived;

   await socketListener.BindServiceNameAsync( 
      rfcommProvider.ServiceId.ToString(),
      SocketProtectionLevel.BluetoothEncryptionAllowNullAuthentication);

   rfcommProvider.StartAdvertising(socketListener);
}

当 protectionLevel 参数 SocketProtectionLevel.BluetoothEncryptionAllowNullAuthentication 更改为 SocketProtectionLevel.PlainSocket 作为异常指示时，新的异常消息为：System.Exception: 'The specified class was not found. (Exception from HRESULT: 0x8007277D)'.

应用清单文件包括：

<Capabilities>
   <Capability Name="internetClient" />    
   <DeviceCapability Name="bluetooth" />
   <DeviceCapability Name="proximity" />
   <DeviceCapability Name="serialcommunication">
     <Device Id="any">
        <Function Type="name:serialPort" />
     </Device>
   </DeviceCapability>
   <DeviceCapability Name="bluetooth.rfcomm">
      <Device Id="any">        
         <Function Type="name:serialPort" />       
      </Device>
   </DeviceCapability>
   <DeviceCapability Name="wifiControl" /> 
</Capabilities>

根据以下文档，这段代码似乎应该可以工作： https://docs.microsoft.com/en-us/uwp/api/windows.networking.sockets.streamsocketlistener#Windows_Networking_Sockets_StreamSocketListener_BindServiceNameAsync_System_String_Windows_Networking_Sockets_SocketProtectionLevel_Windows_Networking_Connectivity_NetworkAdapter_

我做错了什么？

Answer 1

只需更改 BindServiceNameAsync 方法的参数，

rfcommProvider.ServiceId.ToString()

至

rfcommProvider.ServiceId.AsString()

那么你的代码片段就可以工作了。

RfcommServiceId 的 AsString() 方法会将 RfcommServiceId 转换为字符串。ToString 会将 return 类型转换为不正确的参数BindServiceNameAsync.

更多详情请参考official sample。

UWP RfComm - StreamSocketListener.BindServiceNameAsync 抛出异常

UWP RfComm - StreamSocketListener.BindServiceNameAsync throws exception

bluetooth

uwp

serial-port

listener

rfcomm