OnPagePropertiesChanging not firing

I'm using a ListView and a DataPager to display a list of dates from a datatable.  I can bind the ListView and display the pagination, but when I click on a page in the pagingation the  PagePropertiesChanging event never gets fired in my code-behind.  If I change the PageSize property, the DataPager changes appropriately, so the pagination is "hooking" up to the ListView find, it just doesn't page.  Here is my code:
 
<asp:ListView ID="lvDates" runat="server" OnPagePropertiesChanging="lvDates_PagePropertiesChanging">
<LayoutTemplate>
</LayoutTemplate>
<ItemTemplat ...