How to create an event by a self-made control?

Hello!

I am working on my first C# and .NET project that uses WinForms, as WPF would be an overkill for our purposes. I created a so-called ButtonMenu that comprises of all menu points, which are buttons. This class is derived from the Windows class Control.

One of the buttons of the ButtonMenu is the „Culture“ button that, when pressed in this single-touch application, should change the language of all the forms the application has.

Originally, the ButtonMenu was just a kind of overlay class that accessed the controls of the BaseForm and contained methods. The BaseForm was holding the buttons inside a GroupBox of its own. Later, I run into problems with this kind of design and decided to make a separate control out of it.

My question
How can I create an event (or something similar to it) that can be caught by BaseForm, where the ButtonMenu is placed? The BaseForm can currently not react on this event and cannot change the language of all its own controls, such as text fields and buttons.

Thank you for your help!