How to set the values in associated control.

I have created a web user control for numeric pad to enter numbers for touch screen application.
<asp:Panel ID="pnlPopUp" runat="server">
    <table>
        <tr>
            <td>
                <asp:Label ID="lblNumbers" runat="server" Text="Numbers:" />
            </td>
            <td>
                <asp:TextBox ID="txtNumbers" runat="server" />
            </td>
        </tr>
 & ...