<asp:dropdownlist id="ddlDesignation" runat="server" xmlns:asp="#unknown"></asp:dropdownlist>
<asp:requiredfieldvalidator id="RequiredFieldValidator3" runat="server" controltovalidate="ddlDesignation" xmlns:asp="#unknown">
ErrorMessage="Please select your designation." ValidationGroup="submit" InitialValue="-1" SetFocusOnError="True" CssClass="Validators"></asp:requiredfieldvalidator>