public static DatabaseSystem GetInstance()
{
if (ds == null)
{
ds = new DatabaseSystem();
}
return(ds);
}
public List <Category> GetCategories()
{
List <Category> categories = new List <Category>();
foreach (Product p in contents)
{
Category c = DatabaseSystem.GetInstance().
GetCategoryOfProduct(p.ProductID);
if (!categories.Contains(c))
{
categories.Add(c);
}
}
return(categories);
}
public Boolean Add(int productId, int quantity)
{
Product product = contents.FirstOrDefault(p => p.ProductID == productId);
if (Object.Equals(product, null))
{
product = DatabaseSystem.GetInstance().GetProductForId(productId);
contents.Add(new Product(product.ProductID, product.CategoryID,
product.Title, product.ShortDescription, product.LongDescription, product.Price, quantity));
numItems++;
totalCost += product.Price * quantity;
}
else
{
product.Quantity += quantity;
totalCost += product.Price * quantity;
}
return(true);
}