I've posted this to MSDN forums also, but maybe I can get feedback from
here too. Here it goes:
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Hi all,

Dear Community,
I have a very strange error that started to occur two weeks ago. When I run
an Application that worked without problems for nearly half a year now, there
suddenly is one function which I am calling via PInvoke that sometimes fails.

I have a project where I use the MFC support for interop: <afxwinforms.h>,
CWinFormsControl<Ctrl> etc. This works fine exept for some problems when the
application closes down. Now and then I get an ASSERT in wincore.cpp l .2870
(WalkPreTranslateTree). Further I can see in the ...

When passing data to an unmanaged DLL, is there much of a performance
difference between passing a structure versus an object that is
marshalled as a structure? Is there another option I have not thought
of? Below is an example...

I'm doing a screen saver. When it comes to display a preview, Windows sends
a /p argument followed by a space and a hWnd...  When I send this hWnd to
IsWindowVisible((IntPtr)hWnd); I always receive false...
my definition for IsWindowVisible is like this :

[STAThread]
       static void Main()
       {
           ApartmentState x =

I have an unmanaged dll which returns a BSTR* allocated using a
SysAllocString on the unmanaged code.
Now when this BSTR is returned to the Managed world, will the memory
allocated to the BSTR be freed by GC or do I need to take care of

I have a very simple C# library that demonstrates a problem that I am trying
to figure out right now. I could post a full example, if this forum allowed
posting attachments.
Anyway, like I said, I have a very simple C# class...

I am having an issue creating a type library for one of my assemblies.
I recompiled a 1.1 assembly into the 2.0 framework and now when I run
regasm, the types do not get exported properly.  The 1.1 regasm tool
properly exports the 1.1 assembly, but the 2.0 regasm tool errors on

I've an ActiveX made using MFC that has a method that shows a modeless dialog
box containing a Tree control (SysTreeView32).
This ActiveX is used inside a C++ MFC application and it works fine.
When I use this ActiveX inside a C# application the bitmaps associated to

I have an unmanaged  c++ dll which exports the  function:
long GetAllFormationNames(long LithSchemeID, long LevelID,  int &
numData, long ** Ids, char *** Names);
it's the final argument that I am having trouble converting/calling

The project I am developing uses a third party COM component which references
both the Microsoft ActiveX Data Objects 2.7 Library and the Visual Basic for
Applications COM objects. When I add the third party component to my project
the other two get added automatically as ...

I have created an application in C# that converts HTML file to MS word
documents. The HTML file may also have images , for e.g "<img
src='http://www.google.com.pk/images/hp0.gif'></img>".
The HTML file saved into .doc file. Now the problem is

I notice that anytime I run Regasm to register a managed library for
COM-interop that it registers it with a threadingmodel of "Both".  I have a
particular library that can display forms, and therefore, I believe, must run
in an STA.  Is there control over this?  I do note that ...

Please, anyone can help me? I need a invoke a C function from a unsafe
DLL. How to make a Dllimport call in C#?
There´s the function:
CLASS_DECLSPEC void WINAPI RCAL1901(const char *entrada,char *saida)