Question

我有一个问题我尝试通过套接字从node.js服务器读取uwp应用程序中的字符串，但没有成功。我有一个System.Runtime.InteropServices.COMException，我不知道如何解决它。我设法从uwp客户端向节点服务器发送一个字符串，但我不能这样做。这是我的代码我做错了什么？

这是我的node.js服务器代码

  public async Task connect()
        {


            try
            {
                HostName hostName;

                hostName = new HostName(SocksParameters.Host);
                socket.Control.NoDelay = false;
                var cts = new CancellationTokenSource();
                cts.CancelAfter(SampleConfiguration.timeout);

                // Connect to the server
                var connectAsync = socket.ConnectAsync(hostName, SocksParameters.Port);
                var connectTask = connectAsync.AsTask(cts.Token);
                await connectTask;
            }
            catch (Exception e)
            {
                Debug.WriteLine(e.ToString());
                await new MessageDialog("Make sure your Server is open and make sure you follow Instructions To connect localhost").ShowAsync();
                Application.Current.Exit();
            }

        }

public async Task<String> read()
        {
            DataReader reader;
            StringBuilder strBuilder;



            using (reader = new DataReader(socket.InputStream))
            {

                try
                {
                    strBuilder = new StringBuilder();
                    reader.InputStreamOptions = Windows.Storage.Streams.InputStreamOptions.Partial;

                    reader.UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf8;
                    reader.ByteOrder = Windows.Storage.Streams.ByteOrder.LittleEndian;

                    await reader.LoadAsync(256);
                    while (reader.UnconsumedBufferLength > 0)
                    {
                        strBuilder.Append(reader.ReadString(reader.UnconsumedBufferLength));
                        await reader.LoadAsync(256);//System.Runtime.InteropServices.COMException Exception caught
                    }

                    reader.DetachStream();
                    return strBuilder.ToString();
                }
                catch (Exception e)
                {    
                    return (e.ToString());

                }
            }

        }

这是我的UWP代码

  Activated Event   Time    Duration    Thread
    Exception thrown: 'System.Runtime.InteropServices.COMException' in mscorlib.ni.dll ("The I/O operation has been aborted because of either a thread exit or an application request.

The I/O operation has been aborted because of either a thread exit or an application request.
")  0.55s       [18700] <No Name>

Rails 4.1.0

Answer 1

我测试了代码，我发现如果DataReader对象reader无法读取更多数据，代码行await reader.LoadAsync(256);将始终等待，直到新消息从服务器和DataReader可以读取它。在您的代码中，如果来自服务器的数据大小小于256，则第二次调用LoadAsync方法可能会导致问题。

 await reader.LoadAsync(256);
 while (reader.UnconsumedBufferLength > 0)
 {
     strBuilder.Append(reader.ReadString(reader.UnconsumedBufferLength));     
     await reader.LoadAsync(256);
      //System.Runtime.InteropServices.COMException Exception caught
 }

我在这里提供的解决方法是判断是否可以读取剩余数据。更新后的代码如下：

 var loadsize = await reader.LoadAsync(256);
 while (loadsize >= 256)
 {
     loadsize = await reader.LoadAsync(256);
 }
 if (reader.UnconsumedBufferLength > 0)
 {
     strBuilder.Append(reader.ReadString(reader.UnconsumedBufferLength));
 }

在我看来，您似乎可以使用StreamReader，它也适用于您的方案，而不是DataReader，因为它更简单易用。代码如下：

Stream streamIn = socket.InputStream.AsStreamForRead();
StreamReader reader = new StreamReader(streamIn);
string response = await reader.ReadLineAsync();
return response;

有关uwp中StreamSocket的更多详情，请参阅official sample。

无法通过Node.js到UWP应用程序的套接字接收数据

1 个答案: