A: 

Finally I found out it happen only when i use Master page , But i don't know why .

Mostafa  2010-01-07 19:03:07

related questions

Is it better to create Model classes, or just stick with generic database utility class?
What are effective options for embedding video in an ASP.NET web site?
Visual Studio 2008 debugger already attached work-around
Tracking state using ASP.NET AJAX / ICallbackEventHandler
ASP.NET Display SVN Revision Number
ASP.NET URL Rewriting
How can I change the background of a masterpage from the code behind of a content page?
Easy way to AJAX WebControls
How do I define custom web.config sections with potential child elements and attributes for the properties?
ASP.NET MVC "CRUD" Database Sample
Are Multiple DataContext classes ever appropriate?
How to RedirectToAction in ASP.NET MVC without losing request data
Triple Quotes? How do I delimit a databound Javascript string parameter in ASP.NET?
ASP.NET built in user profile, Vs old stile user class/tables
What's a good book for learning ASP?
Bandwith throttling in IIS 6 by IP Address
ASP .Net Custom Client-Side Validation
How to get the value of built, encoded ViewState?
Decent, simple, GIS/mapping component for ASP.NET?
Checklist for IIS 6/ASP.NET Windows Authentication?
How to write to Web.Config in Medium Trust ?
ASP.NET, Visual Studio and Subversion - how to integrate?
Floating Point Number parsing: Is there a Catch All algorithm?
How do I sync the SVN revision number with my ASP.NET web site?
ASP.NET Site Maps