ConversationView.xaml

<UserControl x:Class="ChatBubbles.ConversationView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:ChatBubbles"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="460">

    <UserControl.Resources>
        <local:StringFormatConverter x:Key="StringFormatConverter"/>
         <local:PercentageConverter x:Key="PercentageConverter"/>

        <Style TargetType="TextBox" x:Key="TextBlockStyle">
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="Margin" Value="5"/>
            <Setter Property="TextWrapping" Value="Wrap"/>
            <Setter Property="FontSize" Value="12"/>
            <Setter Property="BorderThickness" Value="0"/>
            <Setter Property="IsReadOnly" Value="True"/>
        </Style>

        <Style TargetType="TextBlock" x:Key="TimestampStyle">
            <Setter Property="Foreground" Value="Green"/>
            <Setter Property="Margin" Value="5"/>
            <Setter Property="FontSize" Value="12"/>
        </Style>

        <DataTemplate x:Key="MeTemplate">            
            <Grid Margin="30, 10, 5, 0"
                      local:GridUtils.RowDefinitions=",,">
                <Rectangle Fill="White"
                           Grid.RowSpan="2"/>
                <TextBox Text="{Binding Path=Text}"
                             Style="{StaticResource TextBlockStyle}"/>
                <TextBlock Text="{Binding Path=Timestamp, Converter={StaticResource StringFormatConverter}, ConverterParameter='ddd, HH:mm'}"
                             Style="{StaticResource TimestampStyle}"
                             Grid.Row="1"/>
                <Path Data="m 0,0 l 16,0 l 0,16 l -16,-16"
                    Fill="White"
                    Margin="0,-1,5,0"           
                    HorizontalAlignment="Right"
                    Grid.Row="2"/>
            </Grid>            
        </DataTemplate>
        <DataTemplate x:Key="YouTemplate">
            <Grid Margin="5, 10, 30, 0" 
                      local:GridUtils.RowDefinitions=",,">
                <Path Data="m 0,0 l 0,16 l 16,0 l -16,-16"
                        Fill="White"
                        Margin="5,0,0,-1"
                        HorizontalAlignment="Left"/>
                <Rectangle Fill="White"
                             Grid.Row="1" Grid.RowSpan="2"/>
                <TextBox Text="{Binding Path=Text}"
                             Style="{StaticResource TextBlockStyle}"
                             Grid.Row="1"/>
                <TextBlock Text="{Binding Path=Timestamp, Converter={StaticResource StringFormatConverter}, ConverterParameter='ddd, HH:mm'}"
                             Style="{StaticResource TimestampStyle}"
                             Grid.Row="2"/>
            </Grid>
        </DataTemplate>
    </UserControl.Resources>

    <Grid x:Name="LayoutRoot" Background="Black">
        <ItemsControl ItemsSource="{Binding}">
            <ItemsControl.ItemTemplateSelector>
                <local:MessageTemplateSelector
                MeTemplate="{StaticResource MeTemplate}"
                YouTemplate="{StaticResource YouTemplate}"/>
            </ItemsControl.ItemTemplateSelector>
        </ItemsControl>
    </Grid>
    
</UserControl>