WaitHandle.WaitOne uses MsgWaitForMultipleObjects. I know this because when it is called on the UI thread messages are still pumped.

Tnx. I have seen that previous post of yours before. I am able to call the exported class methods. The issue with callback function, I think I have it right now, is by modifying the C++ DLL source. Added the __stdcall to the Callback method declaration. Is this okay? bool mapImage(UINT16 iSectorSize, bool (__stdcall * pCallback)(UINT32, UINT8 *, bool)) Tnx for the help. Vini

Hi Vini, I am also having the same problem using bit fields in C#. Is it possible for you to post ur sample code? Thanks, - Prerna

Hai Vini Deep, My need is same as your problem. Please reply if you have solved it. Thanks friend.

If you want to use C++ classes that are exported from a DLL, you should write a simple wrapper class library in Managed C++. You can then use that wrapper class library from your other .NET projects. For more details and a simple sample project, look at: http://www.codeguru.com/Cpp/Cpp/cpp\_managed/interop/article.php/c6867/

You can do this using a class factory and the CallingConvention.ThisCall calling-convention. See the CallingConvention enumeration[^] documentation for a little information about the various calling conventions and how they're used, and a previous post of mine about how to use it: http://www.codeproject.com/script/comments/forums.asp?msg=771919&forumid=1649&XtraIDs=1649&searchkw=ThisCall&sd=11%2F15%2F1999&ed=4%2F12%2F2004#xx771919xx[^]. Microsoft MVP, Visual C# My Articles

tlbimp.exe only works on COM servers with type libraries (typelibs). If you need to call native APIs that are exported from your DLL, you need to use P/Invoke. See Interoperating with Unmanaged Code[^] in the .NET Framework SDK for the differences between CCWs, RCWs, and P/Invoke, as well as click "Search comments" above. It's been discussed in this forum more times than you can imagine and there are also MANY articles about both types of interop here on CodeProject and across the 'net. Microsoft MVP, Visual C# My Articles

Thanks.. but the dlls and lib's I have created , I want to test it from a vc.net debugger. So, as the first step i wanted to execute the existing vc6.0 project in .net framework. Can anyone help me with the compiler options? How to link multiple lib files(system lib and user libs), during compilation. Thanks... Vini

What are the #include's needed for this code? I'm compiling for Win32 and I haven't been able to figure out the right combination of files thanks

There is probably more than one site that provides this information. For a quick reference to code that handles these formats, I would reccomend seeing the article CxImage (@ codeproject) it should point you in the right direction. There is also a book (that is out of date call "Graphics File Formats" with CD) that may be of some help. INTP