CODEWITHSUNDEEP
wpfobservablecollection
Fred Jand
Fred Jand

Reputation: 699

CollectionChanged event of ObservableCollection

I have an ObservableCollection, this collection has 2 items (model), the model has Value as a property.

there is an event CollectionChanged for the collection, which suppose to fire when an item is changed, so I am expecting to see this event get fire when a model Value sets but I don't how model should be structured to fire that event?

I know that Model can have an event and when a Model is added a handler can be assigned to this event, but I want to know how CollectionChanged works for change of item in the collection?

Upvotes: 1

Views: 2521

Answers (3)

Project Kemah
Project Kemah

Reputation: 1

A hack is to add a new element to the collection and remove it immediately. That will raise the collectionchanged event.

Upvotes: 0

Jon
Jon

Reputation: 437754

CollectionChanged will only be raised when a model replaces another in your collection. Property changes to a model that is already inside the collection will not raise it.

You will need to handle those with the INotifyPropertyChanged.PropertyChanged event, which your models must expose.

Upvotes: 3

Reed Copsey
Reed Copsey

Reputation: 564841

It won't fire if a property within the element is changed, only if you assign a new "model" item to an index of the collection.

If you want WPF to update when you change a property value within your Model class, you need to make the model instances implement INotifyPropertyChanged.

Upvotes: 2

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