how to display selected data from dropdownlist in grid view in C# language

Question

hi frnds,

              I have a dropdown listbox , in that I want to show different branches of college in that.

when user selects one of the value from the  drop-down listbox then the data corresponding to that branch( drop-down listbox) has to be displayed in the grid view  C# language .
for example :

   when user selects "information technology" from drop-down list box then list of faculty members related to information technology  has to be displayed in grid view