To make an ASP.NET control validator recognize an alternate date format such as DD/MM/YYYY, set the culture at the page level with:
Page.Culture =
"en-AU";
This will set the validators for Australian English, and the following validator will work correctly:
<asp:CompareValidator ID="cvStartDate" runat="server" ControlToValidate="txtStartDate" ErrorMessage="The From Date should be in the format DD/MM/YYYY." Operator="DataTypeCheck" Type="Date">*</asp:CompareValidator>