When you create a Windows Forms control to perform a task, you can save that control and import it into any Windows Forms application where you want to perform that task. Creating the control saves you from having to write the same code in multiple projects.
This video shows you how to create a simple control that increments a number every time you click it. The following tasks are included in the process:
How to create a project in C++.
How to create a user interface.
How to add C++ code to make the control work.
How to add the control to the Visual Studio Toolbox.
How to create a second project in your solution to test the control.
How to run and test your program.
The Visual C++ Help includes the code and the steps that are demonstrated in this video. See Creating a Windows Forms Control (C++).