Hello,
I have an existing application written with CVI 9.0.1, which have to interact with a C# 2010 dll (which doesn't have any window) via a CVI<->.net wrapper (created using the usefull .net controller of CVI).
This C# dll uses asynchronuous functions, like NetworkStream.BeginRead() and EndRead() functions of a System.Net.Sockets.TcpClient object for example.
These asynchronuous functions work fine when the C# dll is used by a C# application (having a main window) or when the C# dll is converted in a standalone C# program (having a main window with buttons, to call its methods, just to try), but asynchronuous functions don't work when my C# dll is called by my CVI application (which is my goal): execution stays inside NetworkStream.BeginRead() for example (for the concerned thread).
NetworkStream.BeginRead() can be successfully bypassed by using the synchronuous function NetworkStream.Read() instead, but the C# dll uses others asynchronuous functions wich have no associated synchronuous functions.
Here is a portion of C# code (I don't have the source code for the Snmp object ; got_trap() method is never called when asynchonuous calls don't work):
public void run() // the thread
{
Snmp snmp = null;
try
{
snmp = new Snmp(true);
snmp.NotifyListenPort = 162;
snmp.NotifyRegister(null, null, new NotifyCallback(got_trap), CB_DATA_);
isActive = true;
Thread.Sleep(Timeout.Infinite);
}
...
}
Thinking it could be a problem with window messages which could be not processed (in the C# dll), I tried to replace the Thread.Sleep(Timeout.Infinite) instruction, in the code where the asynchronuous management take place, by a window creation plus my Win32 window message loop, but asynchronuous functions don't work better (whereas my loop seems to successfully process messages):
Form myForm = new Form(); // an empty window
myForm.Show();
int bRet;
MSG msg = new MSG();
while ((bRet = GetMessage(out msg, IntPtr.Zero, 0, 0)) != 0)
{
if (bRet == -1)
{
// handle the error and possibly exit
}
else
{
switch (msg.message)
{
default: // everything else
TranslateMessage(ref msg);
DispatchMessage(ref msg);
break;
}
}
}
Any idea ?
Thank you,
rvfr.
