没有收到所有数据与networkstream.read

Question

我使用下面的代码从服务器获取新闻组：

sendBytes = Encoding.ASCII.GetBytes("LIST active microsoft.public*" & ControlChars.CrLf) 
networkStream.Write(sendBytes, 0, sendBytes.Length) 
Array.Clear(bytes, 0, bytes.Length) 
If networkStream.CanRead Then 
    Do 
     numberOfBytesRead = networkStream.Read(myReadBuffer, 0, myReadBuffer.Length) 
     myCompleteMessage.AppendFormat("{0}", Encoding.ASCII.GetString(myReadBuffer, 0, numberOfBytesRead)) 
     intLenMyReadBuf = myReadBuffer.Length 
     intLenComplMsg = myCompleteMessage.Length 
     swWriter.WriteLine("buf len = " & intLenMyReadBuf & ", msg len = " & intLenComplMsg) 
     Loop While networkStream.DataAvailable 
Else 
    Console.WriteLine("Sorry. You cannot read from this NetworkStream.") 
End If 

sendBytes = Encoding.ASCII.GetBytes("QUIT " & ControlChars.CrLf) 
networkStream.Write(sendBytes, 0, sendBytes.Length) 
tcpClient.Close() 
networkStream.Close() 

当我执行的代码，程序只接收一个数据块。但是，如果我在循环指令中使用带有断点的 调试模式，则会收到所有数据块。
我是否在代码中遗漏了一些东西，比如等待什么东西，这会让程序
接收调试时发生的所有数据？

Answer 1

问题是，你正在循环，直到networkStream.DataAvailable不正确。在正在运行的应用程序中，您的循环可能执行得太快以至于发件人没有时间再次填充缓冲区。

您需要循环直到满足特定条件。例子：

1）所有你期待已接收到的数据的

2）特定的组已收到

3）特定的时间已经达到极限数据（即EOF）的（即如果你30秒内没有收到任何数据，保释）。如果你处于一个无限循环，你应该始终执行这样的事情，除非你打算让这个过程永远持续下去。

我会处理更改为类似：

Dim fLoopDone As Boolean 
' Initialize the timestamp for the last data that was read so that we wait up to 30 seconds 
' at the start for data. 
Dim dtLastData As DateTime = Date.Now 
Do 
    ' Only process the data if there is some available. 
    If networkStream.DataAvailable Then 
     numberOfBytesRead = networkStream.Read(myReadBuffer, 0, myReadBuffer.Length) 
     myCompleteMessage.AppendFormat("{0}", Encoding.ASCII.GetString(myReadBuffer, 0, numberOfBytesRead)) 
     intLenMyReadBuf = myReadBuffer.Length 
     intLenComplMsg = myCompleteMessage.Length 
     swWriter.WriteLine("buf len = " & intLenMyReadBuf & ", msg len = " & intLenComplMsg) 

     ' Record the last time that we received data 
     dtLastData = Date.Now 

     ' Possibly add a check in here to see if you are done reading. 
    Else 
     ' If more than 30 seconds has elapsed since the last data arrived, break out of the loop 
     If Date.Now.Subtract(dtLastData).TotalSeconds > 30 Then 
      fLoopDone = True 
     End If 
    End If 
Loop While Not fLoopDone