<asp:DropDownList ID="dlu" runat="server">
<asp:ListItem  Text="一次登陆" Value="0" Selected="false"/>                        
<asp:ListItem  Text="保留一天" Value="1" Selected="false"    />                        
<asp:ListItem  Text="保留一月" Value="30" Selected="false"    />                        
<asp:ListItem  Text="永久保留" Value="365" Selected="false"    />                        
</asp:DropDownList>