I want to have functionality that user can add row in a grid but cannot update the existing data in a grid how we can do. hope you understand my requirement.
If you do not want the user to update an already added row you can handle the CellBeginEdit event and cancel it when you need. The GridViewCellCancelEventArgs allows you to cancel the edit operation by setting the Cancel argument to true. Thus, considering the row/column and row index/ column index, it is possible to restrict entering edit mode in certain cases. More information about the editing lifecycle is available here: Editing Lifecycle - WinForms GridView Control - Telerik UI for WinForms
I hope this infromation is useful. Should you have any other questions do not hesitate to contact me.
Regards,
Nadya | Tech Support Engineer
Progress Telerik