Dynamic add table row in table control

<asp:Table ID="Table1" runat="server" Width="36px">
<asp:Table>

protected void Button1_Click(object sender, EventArgs e)
    {
        TableRow row = new TableRow();
        TableCell cell1 = new TableCell();
        TableCell cell2 = new TableCell();
        TextBox txtt = new TextBox();
       
        txtt.ID = "txt";

        DropDownList dpn_phone = new DropDownList();
        dpn_phone.Items.Add("Home");
        dpn_phone.Items.Add("Work");
        dpn_phone.Items.Add("Mobile");
        dpn_phone.ID = "pho";

        cell1.Controls.Add(txtt);
        cell2.Controls.Add(dpn_phone);
        row.Cells.Add(cell1);
        row.Cells.Add(cell2);

        Table1.Rows.Add(row);
        ph.Controls.Add(t);
    }