private void AddToInventoryClick(object sender, RoutedEventArgs e)
        {
            if (string.IsNullOrEmpty(txtName.Text))
            {
                // TODO: Add notification error saying product name cannot be empty
                return;
            }

            try
            {
                using (var dc = new ProductsDataContext(ProductsDataContext.ConnectionString))
                {
                    var existingProduct = (from p in dc.Products
                                           where p.Barcode == _scannedBarcode || p.ProductName == txtName.Text
                                           select p).FirstOrDefault();

                    Product product;

                    if (existingProduct == null)
                    {
                        product = new Product
                        {
                            ProductName = txtName.Text,
                            Barcode = _scannedBarcode,
                            ImageUrl = _currentProduct.ImageUrl,
                        };

                        dc.Products.InsertOnSubmit(product);
                        dc.SubmitChanges();
                    }
                    else
                    {
                        product = existingProduct;
                    }

                    var purchase = new Purchase
                        {
                            ProductId = product.Id,
                            Currency = txtCurrency.Text,
                            DatePurchased = DateTime.Parse(txtDate.Text),
                            Quantity = int.Parse(txtQuantity.Text),
                            Price = decimal.Parse(txtPrice.Text)
                        };

                    dc.Purchases.InsertOnSubmit(purchase);
                    dc.SubmitChanges();
                }
                // Navigate to main page.
                NavigationService.Navigate(new Uri("/Home", UriKind.RelativeOrAbsolute));
            }
            catch (Exception ex)
            {
                txtName.Text = ex.Message;
            }
        }
 public ProductViewModel(Product product)
 {
     ImageUrl = product.ImageUrl;
     ProductName = product.ProductName;
 }