How to transfer all elements from one project to another?

Question

C++ / C#

I have a project, it was developed for a week, all because I'm a beginner and such things are written in a day, but it doesn't matter. Now I have it as a test project, there is a lot of superfluous stuff and I need to scatter the functions in different places for convenience, so I want to create a new project and copy-paste the functions I need right away to the right places.
But then a question came up. In the constructor, in the code, it is written that a part of the program code is automatically generated, namely, the part that is responsible for the elements and their settings. How to transfer all buttons, textboxes and everything else to a new program?