Prevent tabbing to TextBlock when Visibility is Collapsed - wpf

Question

I'am trying to create a trigger which removes a TextBlock from the tab navigation when the Visibility is Collapsed.
This is the style:
<Style x:Uid="Style_1" TargetType="TextBlock">
<Setter x:Uid="Setter_1" Property="TextOptions.TextFormattingMode" Value="{StaticResource TextFormattingMode}"/>
<Setter x:Uid="Setter_32" Property="TextOptions.TextRenderingMode" Value="{StaticResource TextRenderingMode}"/>
<Setter x:Uid="Setter_2" Property="TextBlock.FontFamily" Value="{StaticResource FontFamily}"/>
<Setter x:Uid="Setter_3" Property="SnapsToDevicePixels" Value="True"/>
<Setter x:Uid="Setter_4" Property="VerticalAlignment" Value="Center"/>
<Setter x:Uid="Setter_74" Property="UseLayoutRounding" Value="True"/>
<Setter x:Uid="Setter_5" Property="Foreground" Value="{StaticResource LabelForeground}"/>
<Setter x:Uid="Setter_7" Property="FontSize" Value="{StaticResource FontSize}"/>
<Style.Triggers>
<DataTrigger x:Uid="DataTrigger_2" Binding="{Binding Source={x:Static cs:ZoomLevel.Instance}, Path=ActualZoomLevelIsDefault}" Value="False">
<Setter x:Uid="Setter_33" Property="TextOptions.TextFormattingMode" Value="Ideal"/>
</DataTrigger>
<DataTrigger x:Uid="DataTrigger_100" Binding="{Binding RelativeSource={RelativeSource Mode=Self}, Path=Visibility}" Value="Collapsed">
<!--<Setter Property="IsEnabled" Value="False"/>-->
<!--<Setter Property="Control.IsTabStop" Value="False"/>-->
<Setter Property="KeyboardNavigation.TabNavigation" Value="None"/>
<Setter Property="KeyboardNavigation.IsTabStop" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
But the TextBlock still gains the focus if I tab to it. IsKeyboardFocusWithin is true when I focus to the TextBlock. I can set IsEnabled to false in my trigger to make it work, but I wonder why the attached property is not working. So my question is: why is the KeyboardNavigation property not working?
Example:
<TextBlock x:Uid="TextBlock_2" Grid.Column="1" Grid.Row="1" Margin="3,3,0,0" HorizontalAlignment="Right" Visibility="Collapsed">
<Hyperlink x:Uid="Hyperlink_2" Command="{Binding SelectRoutingMethods}">
<Run x:Uid="Run_2" Text="{Binding ContactPreferences}"/>
</Hyperlink>
</TextBlock>
The TextBlock is tabable but still visible in my example.

Answer 1

It's not your TextBlock that gets the focus. It's Hyperlink. I don't know why, it's not even in Visual Tree but it does. It seems like a bug. If you set its property Focusable to false it wont take focus anymore.
Here is complete simplified example:
<Window.Resources>
<Style TargetType="TextBlock">
<Setter Property="Focusable" Value="True" />
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=Self}, Path=Visibility}" Value="Collapsed">
<Setter Property="Focusable" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<TextBox>Temp</TextBox>
<TextBlock Visibility="Visible" Grid.Row="1">
<Hyperlink Focusable="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=TextBlock}, Path=Focusable}" Command="{Binding AddOptionalAddressCommand}">test</Hyperlink>
</TextBlock>
<TextBox Grid.Row="2" >Temp</TextBox>
</Grid>

Answer 2

Credits to #Shadowed for finding the issue with hyperlink.
Here is my alternativ solution: set the KeyboardNavigation.IsTabStop on Hyperlink based on the next UIElement visibility up the tree (which will be the TextBlock in this specific case.
<Hyperlink x:Uid="Hyperlink_2" KeyboardNavigation.IsTabStop="{Binding IsVisible,RelativeSource={RelativeSource AncestorType={x:Type UIElement}}}">

Answer 3

As answered by #Shadowed, it was Hyperlink that is getting the Focus. Not sure why this is happening as the Content should not get Focusif the parent is in Collapsed state.
Anyway, I can give you workaround for this.
<StackPanel>
<StackPanel.Resources>
<local:VisibilitytoFocusConverter x:Key="VisibilitytoFocusConv" />
</StackPanel.Resources>
<TextBox >Temp</TextBox>
<TextBlock Visibility="Collapsed" Height="20" KeyboardNavigation.TabNavigation ="{Binding Visibility, RelativeSource={RelativeSource Self}, Converter={StaticResource VisibilitytoFocusConv}}">
<Hyperlink Command="{Binding AddOptionalAddressCommand}" />
</TextBlock>
<TextBox >Temp</TextBox>
</StackPanel>
Converter:
public class VisibilitytoFocusConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo language)
{
return ((Visibility)value) == Visibility.Visible ? "Local" : "None";
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo language)
{
return new NotFiniteNumberException();
}
}
Hope that helps.