Calculation in code behind

Question

Chauffeur service cost $30. It is an option to user whether they want the service or not. When they already select car, and day of rental, I store it in session.

Answer 1

I suggest use Server.Transfer() instead of Response.Redirect() and use PreviousPage to fetch your required values.

This will save you from using Session as Session should not be used in this scenario.

To know how to use PreviousPage see below link.

http://msdn.microsoft.com/en-us/library/system.web.ui.page.previouspage.aspx