Creating specific lambda expression

Question

I've been working on this code for a while now, and am very slow at this point. I don't know if the answer is obvious, but I haven't been able to think of a way to convert this bit:

foreach (Item i in stockList)
{
    if (i == order.OrderItem)
        i.ChangeStock(order.NumberOfItems);
}
outStandingOrders.Remove(order);

into a lambda expression. The best I could come up with is

stockList.ForEach(i => i == order.OrderItem)

(Don't know where to go from here)

There is also only ever one item in stockList that is equal to order.OrderItem.

Any help would be hot

Thanks!

Answer 1

Basing on your information that "There is also only ever one item in stockList that is equal to order.OrderItem", I would write it simply:

 var item = stockList.FirstOrDefault(i => i == order.OrderItem);
 if (item != null)
 {
     item.ChangeStock(order.NumberOfItems);    
 }

Answer 2

stockList.FindAll(i => i == order.OrderItem)
.ForEach(i => i.ChangeStock(order.NumberOfItems));

Untested, just typed ^^