SelectFilePane.xaml

<UserControl
    x:Class="VBA10.SelectFilePane"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:VBA10"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300"
    d:DesignWidth="346">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
          BorderThickness="2,0,2,2" BorderBrush="{ThemeResource ListBoxBorderThemeBrush}">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>
        
        <Grid.Resources>
            <CollectionViewSource x:Name="FileListvs"/>
        </Grid.Resources>


        <StackPanel Background="{ThemeResource ListBoxBorderThemeBrush}"
                    VerticalAlignment="Stretch">
            <TextBlock Text="Assigned at run time" 
                       x:Name="txtTitle"
                       Style="{ThemeResource TitleTextBlockStyle}"
                       Margin="10,4,0,4"
                       />
        </StackPanel>

        <TextBlock x:Name="txtNoFile" Grid.Row="1"
                   Text="**No supported file found!" 
                   Foreground="Red"
                   x:Uid="NoSupportedFile"
                   Margin="10,8,0,8"/>

        <ListBox Name="fileList" 
            Background="Transparent" 
            SelectionChanged="fileList_SelectionChanged"
            ItemsSource="{Binding Source={StaticResource FileListvs}}"
                    Grid.Row="1"
            >
            <ListBox.ItemContainerStyle>
                <Style TargetType="ListBoxItem">
                    <Setter Property="Padding" Value="10"/>
                </Style>
            </ListBox.ItemContainerStyle>
            
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <TextBlock Text="{Binding}" 
                            FontSize="18"/>
                    </Grid>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>


    </Grid>
</UserControl>