根据计数显示多个文本框并插入数据库Asp.net C＃

Question

我正在尝试根据从下拉列表中选择的金额显示一组文本框。假设我选择5然后它应该显示5个文本框;然而，在页面加载时会显示文本框，它会清除框。另外我想输入输入数据库表的那些数据。

protected void ddlCount_SelectedIndexChanged(object sender, EventArgs e)
{       
    ContentPlaceHolder1.Controls.Clear();
    for (int i = 0; i < Convert.ToInt32(ddlCount.SelectedItem.Value); i++)
    {

        TextBox tx = new TextBox();
        tx.ID = "tx" + i;
        ContentPlaceHolder1.Controls.Add(tx);
        ContentPlaceHolder1.Controls.Add(new LiteralControl("&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"));
    }
}

按钮单击

  protected void btnPrint_Click(object sender, EventArgs e)
   foreach (Control ctrl in ContentPlaceHolder1.Controls)
                    {
                        SqlCommand comm = new SqlCommand();
                        {
                        Label ll = (Label)ContentPlaceHolder1.FindControl("Label5");
                        comm.CommandType = CommandType.StoredProcedure;
                            comm.CommandText = "PP_CreateUserNumber";
                            comm.Connection = con;    
                            comm.Parameters.Add("@sealNumber", SqlDbType.NVarChar).Value = 11; 
                            comm.ExecuteNonQuery();
                        }
                    }
 }