private void productDataGridView_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            AddProductUi addProductUi = new AddProductUi(this);

            try
            {
                if (productDataGridView.Columns[e.ColumnIndex].Name == "Edit")
                {
                    if (e.RowIndex < 0)
                    {
                        return;
                    }

                    if (productDataGridView.CurrentRow != null)
                    {
                        productDataGridView.CurrentRow.Selected = true;
                    }

                    //_product.Id = Convert.ToInt32(productDataGridView.Rows[e.RowIndex].Cells[1].Value);
                    addProductUi.id = Convert.ToInt32(productDataGridView.Rows[e.RowIndex].Cells[1].Value);
                    addProductUi.codeTextBox.Text = productDataGridView.Rows[e.RowIndex].Cells[2].Value.ToString();
                    addProductUi.nameTextBox.Text = productDataGridView.Rows[e.RowIndex].Cells[3].Value.ToString();
                    //addProductUi.categoryComboBox.Text = productDataGridView.Rows[e.RowIndex].Cells[4].Value.ToString();
                    addProductUi.categoryText = productDataGridView.Rows[e.RowIndex].Cells[4].Value.ToString();

                    addProductUi.reorderLevelNumericUpDown.Text = productDataGridView.Rows[e.RowIndex].Cells[5].Value.ToString();
                    addProductUi.descriptionTextBox.Text        = productDataGridView.Rows[e.RowIndex].Cells[6].Value.ToString();

                    //MessageBox.Show(addProductUi.categoryComboBox.Text);
                    addProductUi.saveOrUpdateButton.Text = @"Update";
                    addProductUi.categoryErrorLabel.Text = "";

                    addProductUi.ShowDialog();
                }
            }
            catch (Exception exception)
            {
                MessageBox.Show(exception.Message);
            }
        }
        private void addProduct_Click(object sender, EventArgs e)
        {
            AddProductUi addProduct = new AddProductUi(this);

            addProduct.ShowDialog();
        }