server side validation in asp.net?
<p>hi  all as i know that asp.net provide server side validation control which has there own built-in logic, so i want to ask here can we extend built-in logic, i means suppose we use <strong>compare validator</strong> for comparing two file at this point it will validate according to there built-in logic, but i want to add some code for compare validator, is this possible.</p>

<p>According to my knowledge in asp.net every control treated as class which has data and code so according to inheritance  or extend can we add some code in validation control ?</p>
