Does anyone know if there is a way of specifying the Format of a calendar extender with a dynamic value from the aspx? I tried this but it doesnt seem to set the format at all. Does anyone see anything wrong with it: <asp:TextBox ID="tbStartDate" runat="server" /> <act:CalendarExtender ID="clndrStartDate" PopupPosition="Right" runat="server" Format='<%# DefaultDateFormat %>' TargetControlID="tbStartDate"></act:CalendarExtender> and i have the DefaultDateFormat getter in a base page of the code beheind like this: public static string DefaultDateFormat { get { return "dd/MM/yyyy"; } } Any help would be appretiated. Thank you