Fill Combobox of Gridview

[sonia.sardana]

<asp:GridView ID="Grdview1" runat="server" 
AutoGenerateColumns="False" 
AllowPaging ="false" Width="100%" 
>
    <Columns>
        <asp:TemplateField HeaderText="Cities">
        <ItemTemplate >
        <asp:DropDownList ID="cmb1" runat="server" > 
        <asp:ListItem Value="--Select--" Text="--Select--"></asp:ListItem>
        <asp:ListItem Value="Faridabad" Text="Faridabad"></asp:ListItem>
        <asp:ListItem Value="Delhi" Text="Delhi"></asp:ListItem>
        </asp:DropDownList> 
        </ItemTemplate>
        </asp:TemplateField>


        <asp:TemplateField HeaderText="Addresses">
        <ItemTemplate >
        <asp:DropDownList ID="cmb2" runat="server" > 
        </asp:DropDownList> 
        </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

I have two comboxes in GridView named cmb1 & cmb2. On selection Changed of cmb1,I want that cmb2 items to be fill from the database.
How to do dat? I have no idea how to do it. Plz help me!!!!
Thx in advance.