check for duplicates in arraylist

Question

I have an arraylist that contains items called Room. Each Room has a roomtype such as kitchen, reception etc. I want to check the arraylist to see if any rooms of that type exist before adding it to the list. Can anyone recommend a neat way of doing this without the need for multiple foreach loops?

(.NET 2.0)

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I havent got access to the linq technology as am running on .net 2.0. I should have stated that in the question. Apologies

Answer 1

I would not use ArrayList here; since you have .NET 2.0, use List<T> and all becomes simple:

List<Room> rooms = ...
string roomType = "lounge";
bool exists = rooms.Exists(delegate(Room room) { return room.Type == roomType; });

Or with C# 3.0 (still targetting .NET 2.0)

bool exists = rooms.Exists(room => room.Type == roomType);

Or with C# 3.0 and either LINQBridge or .NET 3.5:

bool exists = rooms.Any(room => room.Type == roomType);

(the Any usage will work with more types, not just List<T>)