Može i ovako: u template kolonu ubaci LinkButton. CommandName postavi na "Delete". Na event OnClientClick upiši javascript "return confirm('Da li ste sigurni?');". Kod za brisanje postavi u RowDeleting event handler GridView-a.
Debugging is twice as hard as writing the code in the first place. Therefore, if you
write the code as cleverly as possible, you are, by definition, not smart enough to
debug it. -Brian Kernighan