CODEWITHSUNDEEP
.netwindowsnamed-pipes
Rahul
Rahul

Reputation: 2234

NamedpipeClientStream unable to connect , keeps timing out

I have a Namedpipeserver written largely based on:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa365588(v=vs.85).aspx
When I try to connect to it from a .NET client using this code:

NamedPipeClientStream clientPipe = new NamedPipeClientStream(".",      
    "\\\\.\\pipe\\TTCUIHELPER_SEND_TTC_RECEIVE",PipeDirection.Out);
try
{        

    if (clientPipe != null)
    {
        clientPipe.Connect(5000);
        if (clientPipe.IsConnected == true)
        {
            byte[] bytes = pm.GetMessageData();
            clientPipe.Write(bytes, 0, bytes.Length);
            clientPipe.Flush(); 
            clientPipe.Dispose();
            clientPipe.Close();
        }
    }
}
catch (Exception Ex)
{
    System.Windows.MessageBox.Show(Ex.Message);
}

Then the connect always times out. The weird thing is if I try to write a test client using CPP as so:

LPTSTR lpszPipename = TEXT("\\\\.\\pipe\\TTCUIHELPER_SEND_TTC_RECEIVE");
const TCHAR* lpvMessage=L"QQQQ";

HANDLE hPipe = CreateFile( 
    lpszPipename,   // pipe name 
    GENERIC_READ |  // read and write access 
    GENERIC_WRITE, 
    0,              // no sharing 
    NULL,           // default security attributes
    OPEN_EXISTING,  // opens existing pipe 
    0,              // default attributes 
    NULL);          // no template file 

// Break if the pipe handle is valid. 

DWORD cbWritten;
DWORD cbToWrite = (lstrlen(lpvMessage)+1)*sizeof(TCHAR);
_tprintf( TEXT("Sending %d byte message: \"%s\"\n"), cbToWrite, lpvMessage); 

BOOL fSuccess = WriteFile( 
    hPipe,                  // pipe handle 
    lpvMessage,             // message 
    cbToWrite,              // message length 
    &cbWritten,             // bytes written 
    NULL);                  // not overlapped 

if ( ! fSuccess) 
{
    _tprintf( TEXT("WriteFile to pipe failed. GLE=%d\n"), GetLastError() ); 
    return -1;
}

Then that works flawlessly. What could I be doing wrong that it works from CPP but not .NET?

Upvotes: 3

Views: 1823

Answers (1)

Chris Dickson
Chris Dickson

Reputation: 12135

Just lose the pipe prefix from your pipe name i.e. use just the name itself:

"TTCUIHELPER_SEND_TTC_RECEIVE"

The .NET NamedPipeClientStream class adds the prefix for you when it calls the Windows WriteFile API internally.

Upvotes: 2

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