How to horizontally align AppBarButton in command bar - xaml

Question

I want to align my single AppBarButton to the right on a CommandBar in a Page.BottomBar?
In design it shows the app bar button at the right side but in the emulator, the button is always at the center?
Is there a way to align AppBarButton in a page bottom bar?
Edit:
<Page.BottomAppBar>
<CommandBar HorizontalAlignment="Right" HorizontalContentAlignment="Right">
<CommandBar.PrimaryCommands>
<AppBarButton Margin="100,0,0,0" HorizontalAlignment="Right" HorizontalContentAlignment="Right" IsEnabled="True" Name="btnNext" Icon="Next" x:Uid="AppBarNext" Label="Next1"></AppBarButton>
</CommandBar.PrimaryCommands>
</CommandBar>
</Page.BottomAppBar>

Answer 1

You cannot center buttons in a CommandBar. Having said that, if you need this type of control you simply need to switch to the AppBar control instead. Same behavior, just more flexibility. The trade-off is that this control is not universal and will not render in Phone. You would need to reveal a CommandBar for your Phone platform head.

Answer 2

HorizontalAlignment doesn't work. This is a work around that we use:
<Page.BottomAppBar>
<AppBar IsSticky="true">
<Grid Margin="8,8,8,8">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<AppBarButton Grid.Column="0"
x:Name="SelectButton" Icon="Bullets"
Label="!Select" />
<AppBarButton Grid.Column="1"
x:Name="SelectAllButton"
Icon="SelectAll"
Label="!Select All"/>
<AppBarButton Grid.Column="3"
x:Name="DetailsButton"
Icon="Edit"
Label="!Details"/>
</Grid>
</AppBar>
</Page.BottomAppBar>
And it simply works:
Cheers :P

Answer 3

This works for me getting a left justified back button. It is courtesy of Rudy Huyn's blog at: Display an AppBarButton on the left
<Page.TopAppBar>
<CommandBar>
<CommandBar.Content>
<AppBarButton x:Name="Back" Icon="Back" Label="Back" Click="Back_Click" IsCompact="True"/>
</CommandBar.Content>
<AppBarButton x:Name="videoButton" Icon="Video" Label="Video"/>
</CommandBar>
</Page.TopAppBar>
Rudy has some theories about why Microsoft made it this way. Content on the left everything else on the right.
By the way, that IsCompact="True" is very important or you get annoying labels as well as icons.
Cheers Tim