Thank you so much for trying to help.
In my grid I have a dropdownlist column, when user doublclicking the row, I need to load the data for dropdownlist.
I have looked for a lot of references on the web and finally find a solution that would load the dropdownlist, i am not sure if that's the part that make my BatchEditCommand event not working.
I attached a file for some code I added, please see the attachment.
The Rebind() in ItemCommand event will call NeedDataSource and then radGridStaff_ItemDataBound to load and populate data for dropdownlist.
Then, when I click [savechanges] button, it will trigger BatchEditCommand event, but foreach (GridBatchEditingCommand gridBECmd in e.Commands) with e.Commands.count = 0