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!

• Kamil T: Why do you want to convert it to lambda?
• user3421751: It should be cleaner and I don't know how, so that makes me curious. Based off of the documentation it should be possible.
• Lasse V. Karlsen: Why should it be cleaner? The code looks pretty good to me.
• user3421751: I thought it would be cleaner, I guess that's not the case. Normally it cleans up fairly well. I'm also trying to become more familiar with lambdas.

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); 
 }

• Milan Halada: and what if there are multiple orderitems in stocklist? This would work only for first
• user3421751: There aren't multiple Orders in stockList.
• Milan Halada: oh, missed that line ^^
• sloth: If there's only ever excatly one matching item, I would use Single (or SingleOrDefault if there can be zero matching items). This would make the intent clearer and throw an expection if there are more than a single matching item. If it's wrong if there are more than one matching item, you want to know it as early as possible.
• Scordo: I missed that line, too :-D

Answer 2

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

Untested, just typed ^^

• user3421751: Works like a charm, although it needed one more parenthesis at the end.
• Scordo: Added the missing parenthesis