如何使用验证控件（CompareValidator）判断时间格式

Question

 <asp:TextBox ID="txtNewOperationFromDate" runat="server" MaxLength="10" Width="70px"></asp:TextBox>
                        
                        <asp:CalendarExtender ID="AJAXCalExtNewOperationFromDate" runat="server" TargetControlID="txtNewOperationFromDate"
                            Format="dd/MM/yyyy" />
                        <asp:MaskedEditExtender ID="AJAXMaskNewOperationFromDate" runat="server" Mask="99/99/9999"
                            MaskType="Date" PromptCharacter="_" UserDateFormat="DayMonthYear" TargetControlID="txtNewOperationFromDate"
                            CultureName="en-SG" ClearTextOnInvalid="true">
                        </asp:MaskedEditExtender>
                        &nbsp;&nbsp;&nbsp;&nbsp; 
To
                        <asp:TextBox ID="txtNewOperationToDate" runat="server" MaxLength="10" Width="70px"></asp:TextBox>
                        <asp:CompareValidator ID="NewOperationDate" ValidationGroup="CentreNew" runat="server"
                            ControlToValidate="txtNewOperationToDate" ControlToCompare="txtNewOperationFromDate"
                            Type="Date" Operator="GreaterThanEqual"><%= GetGlobalResourceObject("GlobalResource", "PLEASE_INPUT").ToString()%></asp:CompareValidator>
                        <asp:CalendarExtender ID="AJAXCalExtNewOperationToDate" runat="server" TargetControlID="txtNewOperationToDate"
                            Format="dd/MM/yyyy" />
                        <asp:MaskedEditExtender ID="AJAXMaskNewOperationToDate" runat="server" Mask="99/99/9999"
                            MaskType="Date" PromptCharacter="_" UserDateFormat="DayMonthYear" TargetControlID="txtNewOperationToDate"
                            CultureName="en-SG" ClearTextOnInvalid="false">
                        </asp:MaskedEditExtender>
 2个日期控件 ToDate要大于FromDate 但是ToDate现在 12号以上就报错，例如 24/04/2011
 就指点，我日期格式是 dd/MM/yyyy