How does one determine interface requirements for a given .OCX?

Question

I've a need to analyze an .OCX in order to create a spoof -- the original installation files for this particular component are gone and the company that made it no longer in business. I can identify where it is used in the program that used to use it (and my understanding is that the feature the component made available never worked anyway).

Are there any tools (preferably free) that can do an analysis of .OCX's? The program that uses the component is written in VB6.

NB: As it happened, I mis-stated the problem a bit: I don't have the .OCX, and have to infer its interface from the VB6 project that uses it. And this is 100% Old School VB6. VB6's Object Browser isn't going to help me, and neither is any other OCX analysis tool, sorry. I have to analyze the VB6 project to determine how the OCX is being used, and a tool to do it for me would be what I'm looking for, here.

Answer 1

Microsoft's free OLE / COM Object Viewer tool (OleView.exe) may help you here. Launch the tool, and select "File -> View TypeLib...", then browse to your OCX.

You'll see all of the COM interfaces & coclasses inside the OCX.

Answer 2

I assume you're using Visual Studio .NET. You should be able to go to View->Object Browser. Click the ellipsis (...) and edit custom component set. Then go to the browse tab. Select .OCX in the Files of Type drop down. Then find your file.

VB6 also has an object browser.