Dropdownlist slection chanaged with two ddl in asp.net

Question

Hi,

Kindly share source code there is two dropdownlist one is state another is dist---
want to show when select first dropdownlist state then show all dist of state--in C#.asp.net--with Sql server

Ex--State--delhi then show all dist/town--south ex,lajpatnager,ashokvihar
 

  select  ddl1-delhi then show in ddl2
  south ex
   lahpatnagar
  ashokvihar
Thanks