Create a .dll that references another .dll

Question

I have created a .dll in .Net for a coworker to include in his VB6 project. After a lot of head scratching we finally got the .dll referenced from the VB6 project and were able to create instances of objects.

The thing is my .dll references another .dll (third party). I know when generating .exe files you can choose to include a referenced .dll instead of making it a prerequisite. However the same functionality is not available when creating .dll files.

In his VB6 it mentions that the third party .dll is not accessible.

How can I include the third party .dll in my .dll? Or would it just be wiser for my coworker to reference the third party .dll as well as mine??

Thanks in advance.

Answer 1

You can't (reliably) embed a referenced DLL in another. They both need to be copied to the target machine with their prerequisites and registered/setup as the authors recomend.

Answer 2

In order to reference a .NET DLL from VB6 you will need to run a "regasm" command from the appropriate .NET Framework version. You will also wish to use the "/tlb" switch to have it output the type library (.tlb file).

Once you have the tlb file you can simply choose Project->References from the VB6 IDE and click browse to select the tlb. You can now use early bound instantiation of classes within the .NET library.

Since your .NET DLL uses another DLL you simply need to ensure that it is accessible to the EXE that references your .NET DLL. This is done by deploying the third party DLL to the same path where the EXE launches from or you can also add the third party DLL to the global assembly cache (GAC) if it is also .NET and also strongly named.