Question

Given the code:

var AllItems = new List<CartItem>();

using(var db = new MainContext())
{
    foreach (var item in AllItems)
    {
        if (!db.tblStoreItems.Where(i => i.ID == item.ItemID).Any())
        {
            AllItems.Remove(item);
        }
    }
}

Is this the best way to remove an item from the List object in a loop?

Answer 1

There are several things that are wrong with the loop approach, the main being – you cannot remove items from the collection you’re currently iterating over with foreach – you will get an exception.

Since your main collection is a List<T>, you should use the RemoveAll method that takes in a predicate. You should also simplify your query like this:

AllItems.RemoveAll(item => !db.tblStoreItems.Any(i => i.ID == item.ItemID));