How to deploy C# library with COM interface wrapped in C++?

Question

I've created C# library, but then occurred that it is also needed for some unmanaged C++ solution. I created COM interface (extracted Interface, added GUIDs, created keys, registered and so on).

I've created C++ library which uses tlb file, and creates tlh file. Currently I'm creating some simple UI to check if this wrapper works. My question is - what should I provide to the customer because I have doubts about this "signing" process of COM object. I have to deploy now - one C# library and its wrapper written in C++ (with .h, .lib and .dll - maybe something more?). I don't know if it will start, when it is not registered in user's system? How to handle it that when user get some files he is able to work with them immediately?

Answer 1

You need to create an installer that registers your assembly in the target machine. If you create an msi installer, in the file system editor there is a register property with different options for COM registration. The msi can detect the dependencies of your project output. You can start reading here:

http://msdn.microsoft.com/en-us/library/cc766795.aspx

Answer 2

No, your customers don't need this "C++ wrapper". They can easily generate one themselves, the #import directive in MSVC++ does it automatically for example. It isn't necessary for them to use C++ anyway, COM works in any language. If you include anything at all then consider a demo program that demonstrates how the interface works, also lets them check that everything is installed correctly and in working order.

What your customer needs is the type library, a .tlb file that describes the interface and can be read by most any compiler. Like the #import directive in MSVC++, Project + Add Reference in a .NET project. A type library is the exact same thing as metadata in a .NET assembly. And in the case of a C# [ComVisible] assembly, it is automatically generated from .NET metadata, you run Tlbexp.exe on the assembly. Your customer can do this too, it is better if they do so there's a guaranteed match between the .tlb. But you can do it for them if they are unfamiliar with .NET tooling.

Only thing you must do is write an installer so the assembly is properly registered on the customer's machine. Same thing as Regasm.exe does. Strongly favor the GAC for [ComVisible] assemblies, COM has a nasty DLL Hell problem.