MainPage.xaml

<!-- <SnippetMainPageXAMLFull> -->
<Page
    x:Class="ItemsControlGroupingSnippets.MainPage"
    IsTabStop="false"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:ItemsControlGroupingSnippets"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">
    <UserControl.Resources>
        <!-- <SnippetCVSIsSourceGrouped> -->
        <CollectionViewSource x:Name="cvsActivities" IsSourceGrouped="True"/>
        <!-- </SnippetCVSIsSourceGrouped> -->

        <!-- <SnippetCVSItemsPath> -->
        <CollectionViewSource x:Name="cvsProjects" IsSourceGrouped="True" ItemsPath="Activities"/>
        <!-- </SnippetCVSItemsPath> -->

        <!-- <SnippetGroupStyleSelectorXAML> -->
        <local:ListGroupStyleSelector x:Key="listGroupStyleSelector"/>
        <!-- </SnippetGroupStyleSelectorXAML> -->
    </UserControl.Resources>

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="600"/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>

        <!-- <SnippetGroupedListViewXAML> -->
        <ListView ItemsSource="{Binding Source={StaticResource cvsActivities}}"
          ItemTemplate="{StaticResource listViewItemTemplate}"
          GroupStyleSelector="{StaticResource listGroupStyleSelector}"
          Margin="120" Width="320"/>
        <!-- </SnippetGroupedListViewXAML> -->

        <!-- <SnippetGroupedGridViewXAML> -->
        <!-- <SnippetGroupedGridViewOpenTagXAML> -->
        <GridView ItemsSource="{Binding Source={StaticResource cvsProjects}}" 
          Margin="0,120,0,0" MaxHeight="500" Grid.Column="1">
            <!-- </SnippetGroupedGridViewOpenTagXAML> -->
            <GridView.ItemTemplate>
                <DataTemplate>
                    <StackPanel Margin="20">
                        <TextBlock Text="{Binding Name}" FontWeight="Bold" 
                                   Style="{StaticResource BaseTextBlockStyle}"/>
                        <TextBlock Text="{Binding DueDate}" TextWrapping="NoWrap" 
                                   Style="{StaticResource BodyTextBlockStyle}" />
                        <CheckBox Content="Complete" IsChecked="{Binding Complete}" 
                                  IsEnabled="False"/>
                    </StackPanel>
                </DataTemplate>
            </GridView.ItemTemplate>
            <GridView.ItemsPanel>
                <ItemsPanelTemplate>
                    <ItemsWrapGrid MaximumRowsOrColumns="3"/>
                </ItemsPanelTemplate>
            </GridView.ItemsPanel>

            <GridView.GroupStyle>
                <GroupStyle HidesIfEmpty="True">
                    <GroupStyle.HeaderTemplate>
                        <DataTemplate>
                            <Grid Background="LightGray" Margin="0">
                                <TextBlock Text='{Binding Name}' 
                                           Foreground="Black" Margin="30"
                                           Style="{StaticResource HeaderTextBlockStyle}"/>
                            </Grid>
                        </DataTemplate>
                    </GroupStyle.HeaderTemplate>

                </GroupStyle>
            </GridView.GroupStyle>
        </GridView>
        <!-- </SnippetGroupedGridViewXAML> -->
    </Grid>
</Page>
<!-- </SnippetMainPageXAMLFull> -->