You can inherit your page from the base class. Then you can create a virtual method in your base class, which will be overridden on your page. Then you can call this virtual method from the main page as follows:
(cphPage.Page as PageBase).YourMethod();
Here is the identifier on the main page. is the base class containing the method . cphPage ContentPlaceHolder PageBase YourMethod
: , , YourMethod, .