Drag and Drop not dropping into shopping cart

I can drag the images of album art and they clone and go back to their original place when dropped away from the cart button, but when I drop it on the cart button it doesn't update the cart, it just goes back to its original state. Why is this occuring?

        $("#dr开发者_如何学编程oppable").droppable({
            drop: function (event, ui) {
                var AlbumToAdd = ui.draggable.data("id");
                if (AlbumToAdd != '') {
                    // Perform the ajax post
                    $.post("/ShoppingCart/DragToCart", { "id": AlbumToAdd },
                        function (data) {
                            // Successful requests get here
                            // Update the page elements
                            $('#cart-status').text("Cart (" + data.CartCount + ")");
                        });
                }
            }
        });

Controller

//
// GET: /Store/DragToCart/5
public ActionResult DragToCart(int id)
{
    // Retrieve the album from the database
    var addedAlbum = storeDB.Albums
        .Single(album => album.AlbumId == id);

    // Add it to the shopping cart
    var cart = ShoppingCart.GetCart(this.HttpContext);

    cart.AddToCart(addedAlbum);

    var results = new DragToCartViewModel
    {
        Message = Server.HtmlEncode(addedAlbum.Title) +
            "Your cart has been updated",
        CartTotal = cart.GetTotal(),
        CartCount = cart.GetCount(),
        AddedId = id
    };
    return Json(results);

Comment if you want to see more code

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Have you found out which part of the code doesn't work? Is it the droppable JS or the controller? If you put alert("blah"); in your JS you can find out which code doesn't get triggered.