Solved

var cartItem = _db.ShoppingCartItems.SingleOrDefault(           c => c.CartId == ShoppingCartId

Posted on 2014-09-19
2
307 Views
Last Modified: 2016-02-18
I have the following code from a tutorial and I'm trying to understand the following line of code. I added the full code lenght...

Just having a hard time understanding this sample code bellow...
var cartItem = _db.ShoppingCartItems.SingleOrDefault(
          c => c.CartId == ShoppingCartId
          && c.ProductId == id);


public class ShoppingCartActions : IDisposable
  {
    public string ShoppingCartId { get; set; }

    private ProductContext _db = new ProductContext();

    public const string CartSessionKey = "CartId";

    public void AddToCart(int id)
    {
      // Retrieve the product from the database.           
      ShoppingCartId = GetCartId();

      var cartItem = _db.ShoppingCartItems.SingleOrDefault(
          c => c.CartId == ShoppingCartId
          && c.ProductId == id);
      if (cartItem == null)
      {
        // Create a new cart item if no cart item exists.                 
        cartItem = new CartItem
        {
          ItemId = Guid.NewGuid().ToString(),
          ProductId = id,
          CartId = ShoppingCartId,
          Product = _db.Products.SingleOrDefault(
           p => p.ProductID == id),
          Quantity = 1,
          DateCreated = DateTime.Now
        };

        _db.ShoppingCartItems.Add(cartItem);
      }
      else
      {
        // If the item does exist in the cart,                  
        // then add one to the quantity.                 
        cartItem.Quantity++;
      }
      _db.SaveChanges();
    }

    public void Dispose()
    {
      if (_db != null)
      {
        _db.Dispose();
        _db = null;
      }
    }

Open in new window

0
Comment
Question by:yguyon28
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 

Author Comment

by:yguyon28
ID: 40332531
And also this line of code

 Product = _db.Products.SingleOrDefault(
           p => p.ProductID == id)

Open in new window

0
 
LVL 34

Accepted Solution

by:
it_saige earned 500 total points
ID: 40332558
This line:

var cartItem = _db.ShoppingCartItems.SingleOrDefault(
          c => c.CartId == ShoppingCartId
          && c.ProductId == id);

Basically just means, based on the search criteria [CartID equals ShoppingCartID and ProductID equals id], I am expecting a single cart item.  Give me that single cart item.

If a single cart item cannot be found (or multiple cart items are found), then give me a default cart item (in this case a null object of the same type as cartItem).

The same goes for product.

-saige-
0

Featured Post

Enroll in July's Course of the Month

July's Course of the Month is now available! Enroll to learn HTML5 and prepare for certification. It's free for Premium Members, Team Accounts, and Qualified Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In order to hide the "ugly" records selectors (triangles) in the rowheaders, here are some suggestions. Microsoft doesn't have a direct method/property to do it. You can only hide the rowheader column. First solution, the easy way The first sol…
Article by: Najam
Having new technologies does not mean they will completely replace old components.  Recently I had to create WCF that will be called by VB6 component.  Here I will describe what steps one should follow while doing so, please feel free to post any qu…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…
Visualize your data even better in Access queries. Given a date and a value, this lesson shows how to compare that value with the previous value, calculate the difference, and display a circle if the value is the same, an up triangle if it increased…

615 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question