How to create Add to Cart

Question

I want to make a simple online store that can buy multiple items. Here is my code

public void BuyItem(int deviceid, int quantity)
    {
        Dictionary<int, int> devicelist = new Dictionary<int, int>();
        devicelist.Add(deviceid, quantity);

        Device devices = (from device in master.Devices
                      where device.IDDevice == deviceid
                      select device).SingleOrDefault();
        customer = os.GetCustomer(User);
        //List<CartShop> cartList = new List<CartShop>();
        //var toCart = devices.ToList();
        //foreach (var dataCart in toCart)
        //{
            cartList.Add(new CartShop
            {
                IDDevice = deviceid,
                IDLocation = devices.IDLocation,
                IDCustomer = customer,
                Name = devices.Name,
                Quantity = quantity,
                Price = Convert.ToInt32(devices.Price) * quantity
            });
            cartTotal = cartList;
            StoreTransaksi.DataSource = new BindingList<CartShop>(cartTotal);
            StoreTransaksi.DataBind();
        //}
        X.Msg.Show(new MessageBoxConfig
        {
            Buttons = MessageBox.Button.OK,
            Icon = MessageBox.Icon.INFO,
            Title = "INFO",
            Message = "Success"
        });
    }

But it only can add 1 item, after choose the other item, it replace the old one. (Could not add more than one). Please help

this may be happening since every time BuyItem method is invoked carList may be getting Initialised everytime, — abhi, Dec 28 '16 at 08:09
That's why I make another List `cartTotal = cartList`; that store what is in cartList. But it still doesn't work — Allegra, Dec 28 '16 at 08:11
I'm guessing that cartList is initialised in PageInit or PageLoad event, so it's new every time. `cartTotal = cartList` just copies one list into another. You should keep carList in Session... — Nino, Dec 28 '16 at 08:22

score 1 · Accepted Answer · edited May 23 '17 at 11:46

The issue is that cartTotal is the same as cartList (take a look at this). You need to do the following for copying a list to another without keeping the reference:

cartTotal = new list<cartShop>(cartList);

Also note that this is still in the method and will be created each time you call the method.

Update: This is a very simple console application that does what you need:

internal class Program
{
    public static List<Item> ShoppingCart { get; set; }

    public static void Main()
    {
        ShoppingCart = new List<Item>();
        AddToCart(new Item() { ProductId = 2322, Quantity = 1 });
        AddToCart(new Item() { ProductId = 5423, Quantity = 2 });
        AddToCart(new Item() { ProductId = 1538, Quantity = 1 });
        AddToCart(new Item() { ProductId = 8522, Quantity = 1 });
    }

    public static void AddToCart(Item item)
    {
        ShoppingCart.Add(new Item() { ProductId = item.ProductId, Quantity = item.Quantity});
    }
}

public class Item
{
    public int ProductId { get; set; }
    public int Quantity { get; set; }
}

It still not working, the carTotal still begin from 0 and not store the old value. cartList and carTotal are being global variable — Allegra, Dec 28 '16 at 09:09
If cartList is global, what is cartTotal for? Just remove `cartTotal = cartList;` — Mahdi, Dec 28 '16 at 09:26
cartTotal is for copying a list from cartList since it always new every time. I've been removed `cartTotal = cartList;` — Allegra, Dec 28 '16 at 09:38

How to create Add to Cart

1 Answers1