[BUG] IsListNotNullOrEmptyConverter not working in android

Is there an existing issue for this?

• I have searched the existing issues

Did you read the “Reporting a bug” section on Contributing file?

• I have read the “Reporting a bug” section on Contributing file: https://github.com/CommunityToolkit/Maui/blob/main/CONTRIBUTING.md#reporting-a-bug

Current Behavior

I have an observable collection and would like to enable / disable a button when the collection is empty or has items, but the button is always disabled. I have take a look to https://github.com/CommunityToolkit/Maui/blob/main/samples/CommunityToolkit.Maui.Sample/Pages/Converters/IsListNotNullOrEmptyConverterPage.xaml but I am not able to work with the converter

Expected Behavior

the button is disabled and when I add items to the list, the button is enabled

Steps To Reproduce

Run the attached project on Android. Press “Press to add items” and the “button disabled” should become enabled

Link to public reproduction project repository

https://github.com/acaliaro/MauiAppIsListNotNullOrEmptyConverterProblem

Environment

- .NET MAUI CommunityToolkit:5.0.0
- OS:Android 10
- .NET MAUI:7

Anything else?

No response

[acaliaro]

OnPropertyChanged(nameof(Lista));

this works, thanks @bijington and @brminnick

[bijington]

Oh try this then

OnPropertyChanged(nameof(Lista));

To answer your question directed to @brminnick you don’t need to use [ObservableProperty] with ObservableCollection as it is a special type of collection that handles the raising of events. All other collection types like List will still require the use of the attribute.

I believe the importance of ObservableCollection is not that it implements INotifyPropertyChanged but actually INotifyCollectionChanged. This distinction helps to realise that it is firing events specific to a collection changing and therefore apply to using with controls that have an ItemsSource property.

This might give a little more detail:

https://learn.microsoft.com/en-us/dotnet/api/system.collections.objectmodel.observablecollection-1?redirectedfrom=MSDN&view=net-7.0