Quote:Never pass sensitive data using a query string, because the information is visible to users and can easily be modified, thus representing a potential security risk.
You can use public properties to pass the value in a more secure way. The public properies can be accessed in the next page with the help of PreviousPage
Label1.Text = PreviousPage.ID;
There are other ways too to do this. Check this detailed article in MSDN
How to: Pass Values Between ASP.NET Web Forms Pages
Incase of any doubts, please let me know :)