There are few things to note here.
1) DefaultLabelPosition
can be used in apps targeting Anniversary Update. So if you want to use this for apps targeting previous versions, it would not work.
2) Irrespective of point above, CommandBar.Content
is by itself a separate presenter with AppBarButton
.
How can i get this working?
You can create a style template from default AppBarButton
Template and design your ContentRoot
as required.
Below is the Grid that I changed while playing around sometime before.
<Grid x:Name="ContentRoot" MinHeight="{ThemeResource AppBarThemeMinHeight}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<ContentPresenter x:Name="Content" AutomationProperties.AccessibilityView="Raw" Content="{TemplateBinding Icon}" Foreground="{TemplateBinding Foreground}" HorizontalAlignment="Stretch" Height="20" VerticalAlignment="Center"/>
<TextBlock x:Name="TextLabel" Foreground="{TemplateBinding Foreground}" FontSize="12" FontFamily="{TemplateBinding FontFamily}" Margin="5,0" Grid.Row="0" Grid.Column="1" TextAlignment="Center" TextWrapping="Wrap" Text="{TemplateBinding Label}" VerticalAlignment="Center"/>
</Grid>
Also Style has VisualState Compact
which hides the label text on AppBar Close so comment this out
and then assign this style to your buttons.
<Page.BottomAppBar>
<CommandBar IsOpen="True">
<CommandBar.Content>
<AppBarButton Icon="Account" Label="Test 1" Style="{StaticResource RightAlignAppBarButton}"/>
</CommandBar.Content>
<AppBarButton Icon="Accept" Label="Accept" Style="{StaticResource RightAlignAppBarButton}" />
</CommandBar>
</Page.BottomAppBar>
This is the output

Here is the full style for your reference.
<Style x:Key="RightAlignAppBarButton" TargetType="AppBarButton">
<Setter Property="Background" Value="{ThemeResource AppBarButtonBackground}"/>
<Setter Property="Foreground" Value="{ThemeResource AppBarButtonForeground}"/>
<Setter Property="BorderBrush" Value="{ThemeResource AppBarButtonBorderBrush}"/>
<Setter Property="HorizontalAlignment" Value="Left"/>
<Setter Property="VerticalAlignment" Value="Top"/>
<Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}"/>
<Setter Property="FontWeight" Value="Normal"/>
<Setter Property="Width" Value="68"/>
<Setter Property="UseSystemFocusVisuals" Value="True"/>
<Setter Property="AllowFocusOnInteraction" Value="False"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="AppBarButton">
<Grid x:Name="Root" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" MaxWidth="{TemplateBinding MaxWidth}" MinWidth="{TemplateBinding MinWidth}">
<Grid.Resources>
<Style x:Name="LabelOnRightStyle" TargetType="AppBarButton">
<Setter Property="Width" Value="NaN"/>
</Style>
</Grid.Resources>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="ApplicationViewStates">
<VisualState x:Name="FullSize"/>
<!--<VisualState x:Name="Compact">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>-->
<VisualState x:Name="LabelOnRight">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Margin" Storyboard.TargetName="Content">
<DiscreteObjectKeyFrame KeyTime="0" Value="12,14,0,14"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="MinHeight" Storyboard.TargetName="ContentRoot">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarThemeCompactHeight}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(Grid.Row)" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="0"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(Grid.Column)" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="1"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="TextAlignment" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="Left"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Margin" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="8,15,12,17"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="LabelCollapsed">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="MinHeight" Storyboard.TargetName="ContentRoot">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarThemeCompactHeight}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Overflow">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="ContentRoot">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="OverflowTextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="OverflowWithToggleButtons">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="ContentRoot">
<DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="OverflowTextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Margin" Storyboard.TargetName="OverflowTextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="38,0,12,0"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal">
<Storyboard>
<PointerUpThemeAnimation Storyboard.TargetName="OverflowTextLabel"/>
</Storyboard>
</VisualState>
<VisualState x:Name="PointerOver">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="Root">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBackgroundPointerOver}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="Root">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBorderBrushPointerOver}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="Content">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPointerOver}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPointerOver}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="OverflowTextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPointerOver}"/>
</ObjectAnimationUsingKeyFrames>
<PointerUpThemeAnimation Storyboard.TargetName="OverflowTextLabel"/>
</Storyboard>
</VisualState>
<VisualState x:Name="Pressed">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="Root">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBackgroundPressed}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="Root">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBorderBrushPressed}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="Content">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPressed}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPressed}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="OverflowTextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundPressed}"/>
</ObjectAnimationUsingKeyFrames>
<PointerDownThemeAnimation Storyboard.TargetName="OverflowTextLabel"/>
</Storyboard>
</VisualState>
<VisualState x:Name="Disabled">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="Root">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBackgroundDisabled}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="Root">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonBorderBrushDisabled}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="Content">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundDisabled}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="TextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundDisabled}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="OverflowTextLabel">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource AppBarButtonForegroundDisabled}"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="InputModeStates">
<VisualState x:Name="InputModeDefault"/>
<VisualState x:Name="TouchInputMode">
<VisualState.Setters>
<Setter Target="OverflowTextLabel.Padding" Value="0,11,0,13"/>
</VisualState.Setters>
</VisualState>
<VisualState x:Name="GameControllerInputMode">
<VisualState.Setters>
<Setter Target="OverflowTextLabel.Padding" Value="0,11,0,13"/>
</VisualState.Setters>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Grid x:Name="ContentRoot" MinHeight="{ThemeResource AppBarThemeMinHeight}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<ContentPresenter x:Name="Content" AutomationProperties.AccessibilityView="Raw" Content="{TemplateBinding Icon}" Foreground="{TemplateBinding Foreground}" HorizontalAlignment="Stretch" Height="20" VerticalAlignment="Center"/>
<TextBlock x:Name="TextLabel" Foreground="{TemplateBinding Foreground}" FontSize="12" FontFamily="{TemplateBinding FontFamily}" Margin="5,0" Grid.Row="0" Grid.Column="1" TextAlignment="Center" TextWrapping="Wrap" Text="{TemplateBinding Label}" VerticalAlignment="Center"/>
</Grid>
<TextBlock x:Name="OverflowTextLabel" Foreground="{TemplateBinding Foreground}" FontSize="15" FontFamily="{TemplateBinding FontFamily}" HorizontalAlignment="Stretch" Margin="12,0,12,0" Padding="0,5,0,7" TextAlignment="Left" TextWrapping="NoWrap" Text="{TemplateBinding Label}" TextTrimming="Clip" Visibility="Collapsed" VerticalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
You can play around with few other properties and get the output as desired.