private void update_quantity(int id, int quantity)
{
//TextBox data = (TextBox)sender;
//if (data.Text != null)
//{
//int[] info = data.Text.Split(',').Select(n => Convert.ToInt32(n)).ToArray();
//int cartId = Convert.ToInt32(data);
//int quantity = Convert.ToInt32(info[1]);
//Update purchase with new quantity and refresh page
PurchaseModel cartModel = new PurchaseModel();
cartModel.update_quantity(id, quantity);
Response.Redirect("cart.aspx");
//}
}