God damn it! I specifically told you in your other thread that I had asked the mods to move that thread. You've posted in the wrong forum and now you've compounded that error by posting a duplicate thread. A fine days work. I guess now I'll ask the mods to delete your other thread. I've got nothing better to do.

Anyway, you don't create OCXs in .NET. An OCX is an ActiveX control and ActiveX controls are specifically a COM technology. If you want to create a DLL then you create a Class Library project. Unlike an application project, which compiles to an EXE, a library project compiles to a DLL. If you want to create custom controls that you can use in other projects then you should, if possible, create a Windows Forms Control Library project instead. Some versions/editions of VS don't include that project template, but that's no problem. It's not much different to a Class Library anyway. It just has a couple of extra references (System.Drawing, System.Windows.Forms) and the default item template is a UserControl rather than a Class. Those changes can be made manually very easily.

Just as with any other library, you reference your compiled DLL or, if it's in the same solution, your library project, on the References page of the project properties.