How to put a UserControl into Visual Studio toolBox

Question

I made a usercontrol in my project, and after building project, I need to put it in my toolbox, and use it as a common control. but i can\'t. the UserControl is

Answer 1

In my case, I couldn't see any of the controls in the project. Only when right clicking on toolBox and selecting "Show All" I saw them, but yet they were disabled...

Changing Project type from Windows application to ClassLibrary made the fix.