if session expired i want to redirect to error page

Question

Hi All,

 

 In my application  if session end i want to redirect to login page before redirect to login page i want to show a alert message to indicate the session expire.

or else how to redirect a page using global.asax.

in global.asax page i tried to so many ways to redirect but those are not working

can u please slove my issue.

 

Thanks in advance