private void btnSubmit_Click(object sender, EventArgs e)
        {
            if (!check())
            {
                return;
            }
            bool         result = false;
            InventoryDTO inv    = new InventoryDTO {
                BookID      = txtBookID.Text,
                Index       = txtIndex.Text,
                InventoryID = txtInventoryID.Text,
                Status      = 0
            };

            if (inv.InventoryID == String.Empty)
            {
                MessageBox.Show(this, "The New Inventory is added fail. InventoryID Can't empty!!!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            if (AddOrEdit == 0)
            {
                if (cbStatus.Checked)
                {
                    inv.Status = 1;
                }
                result = bus.AddNewInventory(inv);
                if (result)
                {
                    MessageBox.Show(this, "The New Inventory is added successful", "Notification", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    dr = DialogResult.OK;
                    this.Close();
                }
                else
                {
                    MessageBox.Show(this, "The New Inventory is added fail. InventoryID is existed!!!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
            else
            {
                if (cbStatus.Checked)
                {
                    inv.Status = 1;
                }
                result = bus.UpdateInventory(inv, inv.Status);
                if (result)
                {
                    MessageBox.Show(this, "The Inventory is updated successful.", "Notification", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    dr = DialogResult.OK;
                    this.Close();
                }
                else
                {
                    MessageBox.Show(this, "The Inventory is updated fail. Please try again later.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
        }