Jobs.aspx
This is the phyiscal file -> CodeFile="Jobs.aspx.cs"
This is the class which handles the events of the page -> Inherits="Members_Jobs"
Jobs.aspx.cs
This is the partial class which manages the page events -> public partial class Members_Jobs : System.Web.UI.Page
The other part of the partial class should be -> public partial class Members_Jobs
this is usually the designer file.
you dont need to have partial classes and could declare your controls all in 1 class and not have a designer file.
EDIT 27/09/2013 11:37
if you are still having issues with this I would do as Bharadwaj suggested and delete the designer file. You can then right-click on the page, in the solution explorer, and there is an option, something like “Convert to Web Application”, which will regenerate your designer fil