[Bug] BindingContext default behavior, on nested controls

Description

Hello,

I am trying to bind a Text Property of a control that is inside another, and it does not work.

Let me explain, I was creating kind of an Input layout, like so

public partial class InputLayout : Grid
{
    public static readonly BindableProperty LabelProperty =
        BindableProperty.Create(nameof(Label), typeof(Label), typeof(InputLayout), null, propertyChanged: LabelChanged);

    public static readonly BindableProperty InputViewProperty =
       BindableProperty.Create(nameof(InputView), typeof(InputView), typeof(InputLayout), null, propertyChanged: InputViewChanged);
       
     ...
       
    public Label Label
    {
        get => (Label)GetValue(LabelProperty);
        set => SetValue(LabelProperty, value);
    }

    public InputView InputView
    {
        get => (InputView)GetValue(InputViewProperty);
        set => SetValue(InputViewProperty, value);
    }
    
    ...
    
    private static void InputViewChanged(BindableObject bindable, object oldValue, object newValue)
    {
        if (bindable is not InputLayout intputLayout
            || newValue is not InputView inputView
            || inputView is not IFontElement fontElement) return;

        Grid.SetColumn(inputView, 2);
        Grid.SetColumnSpan(inputView, 1);
        Grid.SetRow(inputView, 1);
        Grid.SetRowSpan(inputView, 1);
        intputLayout.Children.Add(inputView);
    }
}

We should be able to use it like this, But the binding on the Entry does not work anymore…

<controls:InputLayout x:Name="_email" StyleClass="NormalInputLayout">

   <controls:InputLayout.Label>
      <Label Text="Email"/>
   </controls:InputLayout.Label>

   <controls:InputLayout.InputView>
      <Entry
           Keyboard="Email"
           IsTextPredictionEnabled="false"
           Text="{Binding Email, Mode=TwoWay}"/>
   </controls:InputLayout.InputView>
   
</controls:InputLayout>

I also tried to create a intermediate Bindable Text Property in my InputLayout, then bind it progamaticaly, but it also doesn not work.

InputView.SetBinding(InputView.TextProperty, new Binding(nameof(Text)) { Source = this, Mode = BindingMode.TwoWay });

Hope you get it 😃

Steps to Reproduce

1. Take the code below to create a nested control in another one.
2. Add an Entry as the nested control.
3. Try to bind the TextProperty to a stringProperty from the BindingContext.
4. You will never Bind them in anyway (OneWay, TwoWay does not work)…

Link to public reproduction project repository

Does my sample code is enough? Let me know, Regards

Version with bug

6.0.486 (current)

Last version that worked well

Unknown/Other

Affected platforms

iOS, Android, Windows, macOS

Affected platform versions

iOS 16, Mac, Android 12

Did you find any workaround?

You will need to provide a relative Source to make it works.

Text="{Binding Source={RelativeSource AncestorType={x:Type vm:SignInViewModel}}, Path=Email, Mode=TwoWay}"/>

Relevant log output

No response

[SarthakGz]

I am not sure if this should work or not but you can always use relative bindings in that case

[AathifMahir]

This is kind a Sucks, The Intel sense does show the properties for nested controls and binds without any issue but doesn’t work when app launches, On Most Cases We need to use RelativeSource or Reference Markup Extensions to Get Most of it work on Nested Controls with Compiled Bindings with Single Data Context