How to validate server control using class file only

I have been using many ASP.NET forms. Every forms contains "n" number of controls. I want to validate all the controls using one common class file only. For Example, just i want to pass the parameter as control name, then it should validate and check in the class file. So that i have one common file for validation. i don't want to use every page for validation. I want some sample code for one or two controls only with class file validation. All the validation should drive only in class file. Pls. provide some samples using class file. pls. provide one ASPX file with one class file. ...