TextBlock in DataTemplate of ListBox not updating when ObservableCollection<T> that is it's source has one of the properties of T updated

Question

I have a ListBox in an Avalonia project that is bound to an ObeservableCollection<MyType> which is grabbed from an EF Core request _myContext.MyTypes.ToObservableCollection(). For the most part this works great, all the other code related to this works as expected, I can update the content of MyType from DataGrids, etc. The only problem is the TextBlock containing the property I want to display in the list, does not seem to update.

    <ListBox ItemsSource="{Binding MyTypes}" SelectedItem="{Binding CurrentMyType}">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Name}"/>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

I'm not sure why it is not updating, even if I add or remove an item from the bound collection. I was wondering if the Name property needs to be an [ObservableProperty], but that doesn't seem like a good solution to me, as it would be mixing my data layer and presentation layer.

Answer 1

Why would it update? Bindings aren't magic. The binding can set properties on MyType objects by using normal setters, but if MyType does not implement INotifyPropertyChanged (or provide per property change events), the binding has nothing to subscribe to, and neither does the observable collection. A MyType object can be modified by anyone with a reference to the object; bindings and observable collections can't track that.