In this article I will explain how to change alternate row color of Repeater on aspx page. There is no need to manage your own variable. this has the benefit of being completely based in your UI code.
Code: just paste my code in ItemTemplate and it should work.
<%#
Container.ItemIndex % 2 == 0 ? "<div>"
: "<div style='background-color:
#000; padding:2px'>" %>
