Need to compare Two SharePoint Date-time Control in Gridview

Hi,

I am using asp Grid View and Put My two Date controls in it, I need to Check that End Date should be greater than Start Date. asp:CompareValidator does not accept the value to Compare as another control.

here is my code.

<asp:TemplateField HeaderText="Start Date"><ItemTemplate><SharePoint:DateTimeControl ID="StartDate" runat="server" DateOnly="true" UseTimeZoneAdjustment="false" MinDate="" /></ItemTemplate></asp:TemplateField><asp:TemplateField HeaderText="End Date"><ItemTemplate><SharePoint:DateTimeControl ID="EndDate" runat="server" DateOnly="true" />             </ItemTemplate></asp:TemplateField></Columns></asp:GridView></div>

Please help me.

Thanks in advance.

With Thanks and Regards, Azra