خطا در sort کردن گریدویو

[akbarnayebi]

باسلام خدمت دوستان
من توسایتم یک گریدویو استفاده کردم که اطلاعات بصورت کد linq داخل ریختم و در قسمت ویزارد گریدویو سورت پیجش فعال کردم ولی وقتی اجرا میگیرم و میخوام سورت کنم خطای زیر میده،کسی هست که من کمک کنه؟
Server Error in '/' Application. The GridView 'GridView1' fired event Sorting which wasn't handled.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: The GridView 'GridView1' fired event Sorting which wasn't handled.

Source Error:




An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.




Stack Trace:





[HttpException (0x80004005): The GridView 'GridView1' fired event Sorting which wasn't handled.]
System.Web.UI.WebControls.GridView.OnSorting(GridV iewSortEventArgs e) +1588645
System.Web.UI.WebControls.GridView.HandleSort(Stri ng sortExpression, SortDirection sortDirection) +65
System.Web.UI.WebControls.GridView.HandleSort(Stri ng sortExpression) +78
System.Web.UI.WebControls.GridView.HandleEvent(Eve ntArgs e, Boolean causesValidation, String validationGroup) +497
System.Web.UI.WebControls.GridView.RaisePostBackEv ent(String eventArgument) +205
System.Web.UI.WebControls.GridView.System.Web.UI.I PostBackEventHandler.RaisePostBackEvent(String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(IPostBackEve ntHandler sourceControl, String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(NameValueCol lection postData) +9646822
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1724







Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.18067