DropDownList1 RequiredFieldValidator is not working.

<asp:DropDownList ID="DropDownList1" runat="server" AppendDataBoundItems="true"> <asp:ListItem Text="Select Value" Value="0"></asp:ListItem> </asp:DropDownList>
<asp:RequiredFieldValidator id="RequiredFieldValidator2" runat="server" ControlToValidate="DropDownList1" InitialValue="Select Value" ErrorMessage="Select Value required."  ForeColor="Red"></asp:RequiredFieldValidator>        


asp:DropDownList  is displaying static value (Select Value) and dynamic value from database.