Excuse me for sounding like I don't know what I am talking about, but it is difficult to remember everything. I think I could fiil in the missing details of the following but I hope you understand what I am saying.
What command is it that results in the rows being deleted? Is it a toolbar button or a menu item or some other button or what? It seems to me that you could handle the command and then cancel the processing of the command when relevant instead of trying to do it in the row delete event. Do you know what I mean?
Thinking is a feeling; pleasant for some and unpleasant for others.