ItemsControl with databound ItemsSource and two-way binding of elements (replacable items)

Question

I have an ObservableCollection of objects (e.g. Persons with First/Last Name) which I would like to display in an ItemsControl. Each Item is displayed in a custom "editor" control, which allows editing of the object's properties. This part is working fine and fairly standard.

<ItemsControl ItemsSource="{Binding Persons}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <custom:PersonEditor Person="{Binding}" />
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

However, the custom editor control also has the ability to replace the entire object is has received (rather than just editing a person's name, replace it with a new person object).

What I am looking for is a way to push this change back into the ObservableCollection. As it is now, changing the Person object within the editor does not replace the item in the list, which would be the desired outcome.

Any help would be appreciated.

Answer 1

If you don't have access to the custom control itself what you could try would be using a setter on a property to clear the ObservableCollection and re-add the items instead of outright replacing it.

For example:

private ObservableCollection<MyModel> _dataSource;

public ObservableCollection<MyModel> DataSource
{
    get
    {
        return _dataSource;
    }

    set
    {
        _dataSource.Clear();

        foreach(var item in value)
        {
            _dataSource.Add(item);
        }
    }
}

This would prevent the item itself from getting replaced which causes issues with ItemSources since they apparently only bind to the items property once.