Using COM within .NET

  • Thread starter Thread starter Tommy Vercetti
  • Start date Start date
T

Tommy Vercetti

I have a very simple COM object that I want to use within .NET. The COM
object was written in C++/ATL. The object works but the problem is the
COM object never seems to be released and the DLL files can never be
overwritten without restarting the computer.

MyLibrary.CMyCOMClass netWrappedCOMObj = new MyLibrary.CMyCOMClassClass();
try {
// Currently, not using the object, just create/dispose
} finally {
System.IntPtr unknownInterface =
Marshal.GetIUnknownForObject(netWrappedCOMObj);
while
(System.Runtime.InteropServices.Marshal.Release(unknownInterface) > 0);
while
(System.Runtime.InteropServices.Marshal.ReleaseComObject(netWrappedCOMObj)
0);
Click to expand...
netWrappedCOMObj = null;
GC.Collect();
GC.WaitForPendingFinalizers();

// I set a breakpoint here and I can't overwrite the COM DLL file. Why
not?
bool debug = true;
}
 
Tommy Vercetti said:
I have a very simple COM object that I want to use within .NET. The COM
object was written in C++/ATL. The object works but the problem is the COM
object never seems to be released and the DLL files can never be
overwritten without restarting the computer.
Click to expand...

Presumably stopping your .NET application will release the DLL without
rebooting...
MyLibrary.CMyCOMClass netWrappedCOMObj = new MyLibrary.CMyCOMClassClass();
try { // Currently, not using the object, just create/dispose
} finally {
System.IntPtr unknownInterface =
Marshal.GetIUnknownForObject(netWrappedCOMObj);
while (System.Runtime.InteropServices.Marshal.Release(unknownInterface) >
0);
while
(System.Runtime.InteropServices.Marshal.ReleaseComObject(netWrappedCOMObj)
netWrappedCOMObj = null;
GC.Collect();
GC.WaitForPendingFinalizers();

// I set a breakpoint here and I can't overwrite the COM DLL file. Why
not?
bool debug = true;
}
Click to expand...

Releasing all references to an object doesn't unload the DLL. You need to
call (directly or indirectly) CoFreeUnusedLibraries() to get the DLL
unloaded. This is no different in .NET than in native COM development.

-cd
 
Presumably stopping your .NET application will release the DLL without
rebooting...
yes.

Releasing all references to an object doesn't unload the DLL. You need to
call (directly or indirectly) CoFreeUnusedLibraries() to get the DLL
unloaded. This is no different in .NET than in native COM development.
Click to expand...

I suspected that. Thank you very much!

Do you happen to know the .NET way to invoke CoFreeUnusedLibraries()?
 
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