updating the data base by dynamic text boxes

for (int i = 1; i <= a; i++)
            {
                int c = b + i;
                Label lbl = new Label();
                lbl.ID = Convert.ToString(b + i);
                lbl.Text = "flat no."+ c;
                lbl.Width = 70;

                

                Label lbl1 = new Label();
                lbl1.ID = "lbl1" + i+100;
                lbl1.Text = "Size(Sq.ft)";
                lbl1.Width = 70;

                pnlInfo.Controls.Add(new LiteralControl("   "));

                TextBox txt = new TextBox();
                txt.ID = "txt" + i;
                txt.Width = 70;


                pnlInfo.Controls.Add(new LiteralControl("   "));

                Label lbl2 = new Label();
                lbl2.ID = "lbl2" + i+1000;
                lbl2.Text = "type";
                lbl2.Width = 70;

                pnlInfo.Controls.Add(new LiteralControl("   "));

                TextBox txt1 = new TextBox();
                txt1.ID = "text1" + i;
                txt1.Width = 70;

                pnlInfo.Controls.Add(lbl);
                pnlInfo.Controls.Add(new LiteralControl("  "));
                pnlInfo.Controls.Add(lbl1);
                pnlInfo.Controls.Add(new LiteralControl("  "));
                pnlInfo.Controls.Add(txt);
                pnlInfo.Controls.Add(new LiteralControl("  "));
                pnlInfo.Controls.Add(lbl2);
                pnlInfo.Controls.Add(new LiteralControl("  "));
                pnlInfo.Controls.Add(txt1);

                pnlInfo.Controls.Add(new LiteralControl("<br />"));


                Button2.Visible = true;
}

protected void Button2_Click(object sender, EventArgs e)
        {
            int b=Convert.ToInt32(DropDownList3.SelectedItem.Text);
            b=b*100;
            int a = Convert.ToInt32(Label2.Text);
            for (int i = 1; i <= a; i++)
            {
                TextBox txtsize = (TextBox)pnlInfo.FindControl((Convert.ToString("txt" + i)));
                TextBox txttype = (TextBox)pnlInfo.FindControl(Convert.ToString("text1" + i));
                //Label fltno = (Label)pnlInfo.FindControl(Convert.ToString(b + i));

                SqlCommand cmd = new SqlCommand("update flatconfig set size='" + txtsize.Text + "',type='" + txttype.Text + "' where town='" + DropDownList1.SelectedItem.Text + "' and tower='" + DropDownList4.SelectedItem.Text + "' and floor='" + DropDownList3.SelectedItem.Text + "' and flatno='" + i + "'", con);
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
            }
        }