How do you add an existing form to a new project?

Question

I have never been able to successfully add a Form from an existing file to a new project.

I read on a blog that you add just the *.cs file and the depen

Answer 1

Go to solution explorer and right click on it then add existing item, here select the existing form path. Now, and this is important, on the page where you want to use existing form, you must add header file:

using "your existing project name";