//EVENT HANDLERS

        private void ButtonUpdateProduct_Click(object sender, EventArgs e)
        {
            try
            {
                var row = dataGridViewInventory.CurrentRow;

                if (row == null)
                {
                    throw new Exception("Please select an entry to update");
                }

                Inventory product = new Inventory()
                {
                    ProductId       = (int)row.Cells[0].Value,
                    ProductName     = (string)row.Cells[1].Value,
                    ProductQuantity = (int)row.Cells[2].Value
                };

                AddOrUpdateInventoryProductForm updateInventoryProductForm = new AddOrUpdateInventoryProductForm(product);
                HandleForm(updateInventoryProductForm);
            }
            catch (Exception err)
            {
                MessageBox.Show(err.Message);
            }
        }
        public InventoryForm()
        {
            InitializeComponent();

            this.TopLevel        = false;
            this.FormBorderStyle = FormBorderStyle.None;
            this.Visible         = true;
            this.Dock            = DockStyle.Fill;
            this.Load           += InventoryForm_Load;

            InitializeDataGridView <Inventory>(dataGridViewInventory, new string[] { "ProductId", "Services" });
            dataGridViewInventory.DataSource = Controller <BeautySalonEntities, Inventory> .SetBindingList();

            dataGridViewInventory.Refresh();

            AddOrUpdateInventoryProductForm addInventoryProductForm = new AddOrUpdateInventoryProductForm();

            buttonNewProduct.Click    += ButtonNewProduct_Click;
            buttonDeleteProduct.Click += ButtonDeleteProduct_Click;
            buttonUpdateProduct.Click += ButtonUpdateProduct_Click;
        }
        private void ButtonNewProduct_Click(object sender, EventArgs e)
        {
            AddOrUpdateInventoryProductForm addInventoryProductForm = new AddOrUpdateInventoryProductForm();

            HandleForm(addInventoryProductForm);
        }