The functionality you need to achieve is actually not supported by the RadGrid control out of the box. It would not be possible to have two different edit forms with different items in them. Possible option in your case would be to simply use two ButtonColumn with different command names and in the RadGrid ItemCommand event change the edit mode based on the command name of the columns.
In case you need to have one mode for the insert form and the another for the update form you could use the following:
sender, GridCommandEventArgs e)
(e.CommandName == RadGrid.EditCommandName)
RadGrid1.MasterTableView.EditMode = GridEditMode.InPlace;
(e.CommandName == RadGrid.InitInsertCommandName)
RadGrid1.MasterTableView.EditMode = GridEditMode.PopUp;
I hope this helps.
the Telerik team
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