GridView Editing

hi,
firstly i am using DataGrid to display data it is working. present i am using GridView to display data. i am taking one table, that table contains 3 columns i.e. EmpID,Ename,Esal.
i display data in GridView and i take 3 texboxes in bottom of gridview when i click edit link button that row columns are displayed in texboxes here i updated.
EmpID is displayed in Textbox1 and Ename is displayed in Textbox2 and Esal is displayed in Textbox3.
i am using commandArgument prperty in Datagrid  i display records. but in Gridview it is not displayed
Please give a solution of GridView Editing.
Thanks.