Creating methods for validation in C #

Question

How can I create a class and method that are universal for Textbox validation for forms in C#. For example, I need to create a method that validates a field called Name in my customer registration form so that this field is not empty or null I made some code that validated what I wanted, but I had to duplicate this code on multiple forms, making my maintenance and management hard Could someone help me create this method?

Already I thank you.

Eduardo