CODEWITHSUNDEEP
c#.net
Dan
Dan

Reputation: 5972

Detecting a change in a .NET collection or list

I have a class with properties and collections. It also has a property called Dirty. I want to set this Dirty flag if the state of an instance of this class changes in any way.

Obviously for the properties, I can just set this in the setter. However, I'm unsure of the best way of detecting a change in the collection. Whilst I could create my own collection class that derives from the .NET collection class and do it that way, I'm wondering if there's another way which doesn't require my own custom collection type?

Update for clarification

Just to clarify, I don't need to track in a nested way - I literally just want to know if items have been added/removed from the collection.

Upvotes: 2

Views: 2487

Answers (2)

David
David

Reputation: 10708

See ObservableCollection which contains the CollectionChanged event.

Be wary however that ObservableCollections are not thread-safe, though there are several tutorials/articles/projects on how to implement such a thing

Upvotes: 2

BradleyDotNET
BradleyDotNET

Reputation: 61349

With your edit, ObservableCollection<T> would be an excellent choice. It implements INotifyCollectionChanged, so it will raise an event whenever an item is added or removed.

Note that this class is used all the time in WPF for that exact purpose, so the framework can listen to that event and add/remove UI elements as necessary.

Upvotes: 5

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