从主COM服务器中公开的接口创建辅助COM Server

Question

I have a need to define an interface in C# (eg ICommonHandler) and have it implemented in Delphi, or, for that matter any other language. For now, the priority is in Delphi.

From C# I then need to instantiate instances of interface ICommonHandler via classes that's implemented in Delphi.

To summarize the above, I have a 'contract' exposed from C#. My C# code then expects implementations of this contract from Delphi, or then any arbitrary language.

Is the above possible? If so, I'd very much appreciate possible guidelines on how to get it going.

My feeling is that the above will not be possible, because one cannot register multiple COM servers containing the same GUID for the same interface, in this case ICommonHandler.

Answer 1

"My feeling is that the above will not be possible, because one cannot register multiple COM servers containing the same GUID for the same interface, in this case ICommonHandler." That is simply not true! Whoever gave you that idea? If your delphi code exposes ICommonHandler that's enough.

Answer 2

In C#: generate a COM project that compiles to a DLL with just the type library in it, describing ICommonHandler.

In Delphi: import the Type Library from this DLL, optionally having the importer generate wrapper objects for them. (I personally prefer not to and use the raw interface instance references)

Then, using this CommonHandler_TLB.pas in a ActiveX Library project of your own, create descendants of TInterfacedObject or TAutoObject that implement ICommonHandler. If you use the File > New > Other... wizards under ActiveX, a specific ClassID and needed code will be gerated for you.