Using CUDA dll in managed code

Hi all.
I am an brand new in CUDA. How can I use CUDA dll in managed code?
Unfortunatly I could not just add reference in to my project because i got error “Could not add a reference to file …\CudaSource.dll because it is neither a .NET assembly or registered ActiveX control”.

I use the following code in *.h file:
_declspec(dllexport) void Summer(int a, int b);

and in *.cu:
_declspec(dllexport) void Summer(int a, int b)

I use CUDA Toolkit 3.2 and Visual Studio 2008.
Thank you!

In C#, it’s [DLLImport …] that you will need. It’s the same as calling windows API.