Universal App ListView Item HorizontalAlignment - xaml

Question

I would like to create a ListView that has right aligned items as well as left aligned. So far in all my attempts with DataTemplates and ItemContainerStyles, I am not able to get this working. The left alignment works fine as that is the default, but I cannot figure out how to get some items right-aligned. For example, this would be similar to a chat/conversation type view like the Windows Phone Messaging app.
My current XAML looks like this:
<Page
x:Class="MDControl.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MDControl"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<CollectionViewSource x:Name="Messages" Source="{Binding mMessages}"/>
<DataTemplate x:Key="SentMessageTemplate">
<StackPanel Padding="10" Margin="5" Background="Teal" HorizontalAlignment="Right" Width="Auto">
<TextBlock Text="{Binding MessageType}" FontWeight="Bold" TextWrapping="NoWrap" Foreground="White"/>
<TextBlock Text="{Binding MessageBody}" TextWrapping="Wrap" Foreground="White" />
<TextBlock Text="{Binding Timestamp}" TextWrapping="NoWrap" Foreground="White" FontStyle="Italic" FontSize="12"/>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="ReceivedMessageTemplate">
<StackPanel Padding="10" Margin="5" Background="LightGray">
<TextBlock Text="{Binding MessageType}" FontWeight="Bold" TextWrapping="NoWrap"/>
<TextBlock Text="{Binding MessageBody}" TextWrapping="Wrap"/>
<TextBlock Text="{Binding Timestamp}" TextWrapping="NoWrap" TextAlignment="Right" FontStyle="Italic" FontSize="12"/>
</StackPanel>
</DataTemplate>
<Style TargetType="ListViewItem" x:Key="SentMessageStyle">
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
</Style>
<Style TargetType="ListViewItem" x:Key="ReceivedMessageStyle">
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
</Style>
<local:MessageListTemplateSelector x:Key="MessageListTemplateSelector"
SentMessageTemplate="{StaticResource SentMessageTemplate}"
ReceivedMessageTemplate="{StaticResource ReceivedMessageTemplate}">
</local:MessageListTemplateSelector>
<local:MessageListContainerStyleSelector x:Key="MessageListContainerStyleSelector"
SentMessageStyle="{StaticResource SentMessageStyle}"
ReceivedMessageStyle="{StaticResource ReceivedMessageStyle}">
</local:MessageListContainerStyleSelector>
</Page.Resources>
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<ListView x:Name="messageList" ScrollViewer.VerticalScrollBarVisibility="Visible" ItemContainerStyleSelector="{StaticResource MessageListContainerStyleSelector}" ItemsSource="{Binding Source={StaticResource Messages}}" ItemTemplateSelector="{StaticResource MessageListTemplateSelector}" Margin="10,120,10,50" VerticalAlignment="Bottom" IsDoubleTapEnabled="False"/>
</Grid>
What can I change to get the "Sent" messages to be right aligned? Currently they show up with a Teal background which I want, but they are still Left aligned instead of Right. I am a little new to XAML, so forgive me if I'm way off here.
UPDATE: Solution
Grids were the key, I ended up having to use multiple grids to achieve the correct right-alignment, in conjunction with an ItemContainerStyle setting the HorizontalContentAlignment.
<Page
x:Class="MDControl.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MDControl"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<CollectionViewSource x:Name="Messages" Source="{Binding mMessages}"/>
<DataTemplate x:Key="SentMessageTemplate">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid Height="Auto" Grid.Row="1" Margin="5" HorizontalAlignment="Right">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<StackPanel Padding="10" Background="Teal">
<TextBlock Text="{Binding MessageType}" FontWeight="Bold" TextWrapping="NoWrap" Foreground="White" />
<TextBlock Text="{Binding MessageBody}" TextWrapping="Wrap" Foreground="White" />
<TextBlock Text="{Binding Timestamp}" TextWrapping="NoWrap" Foreground="White" FontStyle="Italic" FontSize="12" HorizontalAlignment="Right"/>
</StackPanel>
</Grid>
</Grid>
</DataTemplate>
<DataTemplate x:Key="ReceivedMessageTemplate">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid Height="Auto" Grid.Row="1" Margin="5" HorizontalAlignment="Left">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<StackPanel Padding="10" Background="LightGray">
<TextBlock Text="{Binding MessageType}" FontWeight="Bold" TextWrapping="NoWrap" />
<TextBlock Text="{Binding MessageBody}" TextWrapping="Wrap" />
<TextBlock Text="{Binding Timestamp}" TextWrapping="NoWrap" FontStyle="Italic" FontSize="12" HorizontalAlignment="Right"/>
</StackPanel>
</Grid>
</Grid>
</DataTemplate>
<local:MessageListTemplateSelector x:Key="MessageListTemplateSelector"
SentMessageTemplate="{StaticResource SentMessageTemplate}"
ReceivedMessageTemplate="{StaticResource ReceivedMessageTemplate}">
</local:MessageListTemplateSelector>
</Page.Resources>
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<ListView x:Name="messageList" ScrollViewer.VerticalScrollBarVisibility="Visible" ItemsSource="{Binding Source={StaticResource Messages}}" ItemTemplateSelector="{StaticResource MessageListTemplateSelector}" Margin="10,120,10,50" VerticalAlignment="Bottom" IsDoubleTapEnabled="False">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
</Style>
</ListView.ItemContainerStyle>
</ListView>
</Grid>

Answer 1

The problem is in your DataTemplates , not in styles or etc.You must use Grid instead of Stackpanel in your DataTemplate to achieve that.
Stackpanels won't stretch to parent.They'll only get the width / height of all controls inside it.Try something like
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>

Answer 2

You should use HorizontalAlignment property which defines the position of the element inside a parent element.<Grid x:Name="simpleGrid" height = 50 width = 100 HorizontalAlignment="right" />