protected void btnSave_Click(object sender, EventArgs e)
    {
        bool res = false;

        try
        {
            if (btnSave.Text == "Save")
            {
                ChatLieu.ChatLieu_Insert(tbTenChatLieu.Text, 0);
            }
            else
            {
                ChatLieu.ChatLieu_Update(Convert.ToInt32(hfChatLieuID.Value), tbTenChatLieu.Text);
            }
            res = true;
            Clear();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            res = false;
        }

        if (res == true)
        {
            if (btnSave.Text == "Save")
            {
                lbSuccess.Text = "Saved successfully!!";
            }
            else if (btnSave.Text == "Update")
            {
                lbSuccess.Text = "Updated successfully!!";
            }
        }
        else
        {
            lbError.Text = "There's something wrong. We cannot save your work";
        }
    }