Creation of .Ocx File from a .Net Dll

I have a .Net Com Dll is it possible to use this dll and create .OCX file in c++ 开发者_StackOverflow社区or MFC. If yes what are all the steps which needs to be followed. If any sample code is availabe that would be a great help

You could expose the .NET assembly as COM object using the regasm.exe tool. You could use the [ComVisible(true)] to indicate that all classes should be visible by COM clients when registered. This assembly level attribute could also be set in the properties of the project in Visual Studio. You could also apply it only to some classes that need to be exported. Once the assembly registered as COM object you could instantiate any class from unmanaged clients as with any standard COM object.

There is nothing particularly special about an .ocx file, it is just a DLL. Microsoft came up with that filename extension back in the Visual Basic version 4 days to make it obvious to VB programmers that they had a DLL that contains controls. ActiveX controls as opposed to VBX controls from the 16-bit days.

If you made the .NET assembly [ComVisible] then you already have a COM server that's usable in other projects. Provided you registered it properly, .NET assemblies must be registered with Regasm.exe instead of Regsvr32.exe. Done automatically in a .NET project with the Project + Properties, Build tab, "Register for COM interop" option. And at installation time with a Setup and Deployment project. If you need a type library then use Regasm.exe with the /tlb and /codebase options. Or Tlbexp.exe

If this really needs to be a traditional .ocx, in other words have controls, then you can use a Winforms UserControl or your own class derived from a Winforms control. Winforms automatically implements the plumbing to make classes derived from the Control class function properly in an ActiveX host.

If you're wanting to use a .NET library in normal C++, there are ways, mostly involving COM Interop. Microsoft has a whole section of MDSN dedicated to COM Interop: http://msdn.microsoft.com/en-us/library/6bw51z5z%28v=VS.71%29.aspx.

1. If the .NET DLL supports COM Interop, use that.
2. Try using VC++'s #import directive to read the .NET DLL in as a COM object. When compiled, VC++ should output a .tlh file and a .thi file (header and implementation respectively) which will be automatically compiled into your project. But this may or may not work depending on the DLL's construction, dependencies, etc.
3. Look at creating your own COM Interop .NET wrapper library that marshals calls to the base .NET DLL.