public static void Delete(ProductViewModel product)
 {
     ProductViewModel target = One(p => p.ProductID == product.ProductID);
     if (target != null)
     {
         All().Remove(target);
     }
 }
 public static void Update(ProductViewModel product)
 {
     ProductViewModel target = One(p => p.ProductID == product.ProductID);
     if (target != null)
     {
         target.ProductName = product.ProductName;
         target.UnitPrice = product.UnitPrice;
         target.UnitsInStock = product.UnitsInStock;
         target.Discontinued = product.Discontinued;
         target.LastSupply = product.LastSupply;
     }
 }
        public static void Insert(ProductViewModel product)
        {
            product.ProductID = All().OrderByDescending(p => p.ProductID).First().ProductID + 1;

            All().Insert(0, product);
        }