update: I can now iterate through all the rows that have gotten updated, but am still struggling to figure out which field in the row was updated. According to numerous posts by Telerik staff, the standard way to retrieve oldValues is as noted above (Dim oldValues as hashtable=argument.OldValues). However, I cannot retrieve anything from oldValues.
I can see the new values via newValues("theField").toString.
I cannot see oldValues via a similar call: oldValues("theField").toString
FYI this is the starting portion of the function which iterates through the changed rows.
command.Type = Telerik.Web.UI.GridBatchEditingCommandType.Update
Hashtable = command.OldValues
Hashtable = command.NewValues
One other note for Telerik dev's: Let me know if I should post this as a bug, but if I am in batch edit mode, and simply click my mouse in a dropdown list in a row, but don't change it, and click Update, then that row gets added to the hashtable.