private async void FormAddProductForSaleOrPurchase_Load(object sender, EventArgs e) { try { this.LoadTheme(); cmbIdBrand.DataSource = await BrandService.ListAllBrands(); cmbProductType.DataSource = await ProductTypeService.ListAllProductTypes(); cmbIdBrand.DisplayMember = "nameBrand"; cmbIdBrand.ValueMember = "idBrand"; cmbProductType.DisplayMember = "nameProductType"; cmbProductType.ValueMember = "idProductType"; } catch (Exception ex) { MessageBox.Show(ex.Message); } ClearItems(); txtIdProduct.Focus(); }