e.NeweditIndex property is 0 in Gridview_RowEditing Event

Hi Friends,
On Web Form, I have used gridview in which i have used AutogenerateEditbutton and one Dropdownlist which contains Employee Code.On selection of EmployeeCode from Dropdownlist Gridview gets Filled and user can Edit the Details in Gridview.

my problem is:on selection of Employee Code Gridview gets filled properly, but when i click on the Edit in Gridview after getting the Results as per the selected Employee Code. Gridview gets filled again and i dont get the Editable Record which i have selected Previously.different records gets Edited in my case the First record of the Gridview.

on debuging i get the e.NeweditIndex property is 0.

Please if any of u have any results, do share

Regards,
Aamir