How to dynamically bind data to DropDownList and change datasouce value of GridView in ASP.Net

Hello friend,

I have a problem ,i want to 2 dropdownlist box on a form and one will take loaded from data at the time of pageload and data of second dropdownlist box will change according to selected item in first dropdownlistbox ,and after that gridview will dynamicaly bind from some data according to choosen data of second dropdownlistbox .

I uses lots of code but  i am not able to dynamicaly bind dropdown and gridview  and its very urgent so please help me and send some usefull and easy help .

thanks in advance