Question

I have a header-file, the COM interface. I have created a small win32 program which works, but my main program is written in C#.

So I would like to import this COM object in my main program, but how do I do this, when the only thing I got is the header-file?

All places I’ve looked I need a tlb-file..?

I’m new to COM objects so just ask if you need some extra info, or have another workaround 🙂

[UPDATE]
First thanks for all the responses!
I’ve tried some different things, but haven’t solved my issue yet. In my research, I’ve found an article describing COM Interop http://msdn.microsoft.com/en-us/library/aa645736(v=vs.71).aspx#vcwlkcominteroppart1cclienttutorialanchor2

This haven’t helped me out. But I’ve found that I should be able to get moving if I can complete the following:

1. Declaring a COM coclass:

   [ComImport, Guid("7C075F7F-FD71-40a2-AC63-0D0C4DB39ECA")]
   class CCamera
   {
       // Cannot have any members here 
       // NOTE that the C# compiler will add a default constructor
       // for you (no parameters).
   }
   

2. Creating a COM class wrapper:

   [Guid("AD87369B-3BBA-4f1c-81C5-B92FCEA9A1F4"),
   InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] 
   interface ICamera
   {
       //static HRESULT GetCameraInterface();
       bool StartPreview();
       bool StopPreview();
   }
   

   1. Using Casts Instead of QueryInterface:

   try
   {
   CCamera cam = new CCamera();
   ICamera test = (ICamera)cam;
   //test.StartPreview();
   }
   catch (Exception e)
   {
   Console.WriteLine(e.StackTrace);
   }

I get an invalid cast exception, so is this because I miss implementing some methods in the interface?
And how do I implement the following method from the c++ interface:

static  HRESULT GetCameraInterface(void __RPC_FAR *__RPC_FAR *ppvObject);

[SOLUTION]
OK I got a solution, but I never solved to wrap the interface.
Instead I created a C++ dll project and exposed the methods I needed. Then in my C# project, could I use these methods with DllImport. If anybody need more explanation on how I archived this, send me a message.

Answer 1

If it is registered as a COM-Object, then you can import it via the Add Reference Dialog. Right click on the project –> Add Reference. Then select the Tab “COM” and you can select your COM Interface. Required Interop classes for .NET will be generated automatically.