[Bug] Binding Array Element Directly to Label Text Stopped Working After v 4.1.0.778454

[rmgalante]

Description

I use ObservableCollection with view models that implement BindableBase. Sometimes I need to bind a collection element directly to a label text property, rather than use a repeatable view such as a ListView.

I noticed problems with my app in Android, iOS and UWP after I upgraded to any Xamarin Forms version after 4.1.0.778454. Binding array elements directly stopped working.

Steps to Reproduce

1. Use the attached solution to run the app. It is using XF v 4.1.0.778454.
2. You will see three labels render text.
3. Change the package to any version greater than 4.1.0.778454.
4. The labels do not render.

Expected Behavior

The labels should render.

Actual Behavior

The labels do not render.

Basic Information

I'm stuck at version 4.1.0.778454 at the moment.

• Version with issue: 4.2.0.709249+

• Last known good version: 4.1.0.778454

• IDE: VS 2019

• Platform Target Frameworks:

  • iOS: 9.0+
  • Android: 9.0+
  • UWP: 16299+

• Android Support Library Version:

• Nuget Packages: Microsoft.NETCore.UniversalWindowsPlatform 6.0.12, NETStandard.Library 2.0.3, Prism.Unity.Forms 7.2.0.1367, Android Support Libraries v 28.0.0.3

• Affected Devices: all devices affected

Screenshots

Reproduction Link

DemoBugWhenBindingArrayElement.zip

[rmgalante]

I haven't seen any progress on this issue. This binding issue affects other controls as well. I reported it as affecting the Label. But other elements in XAML that use an array index in the binding have the same issue.