为什么我可以'；t将自定义类作为组绑定到GridView

我试图将一些项目绑定到我的网格视图，但我也想将它们分组。首先，我的xaml是这样的；

<Page.Resources>
        <!-- TODO: Delete this line if the key AppName is declared in App.xaml -->
        <x:String x:Key="AppName">Header</x:String>
        <CollectionViewSource x:Name="itemsViewSource" IsSourceGrouped="True" Source="{Binding Items}"/>
        <DataTemplate x:Key="DataTemplate1">
            <Grid HorizontalAlignment="Left" Width="168" Height="157">
                <Border Background="{StaticResource ListViewItemPlaceholderBackgroundThemeBrush}">
                    <Image Source="{Binding Image}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}"/>
                </Border>
                <StackPanel VerticalAlignment="Bottom" Background="{StaticResource ListViewItemOverlayBackgroundThemeBrush}" Height="48">
                    <TextBlock Text="{Binding Title}" Foreground="{StaticResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource TitleTextStyle}" Height="59" Margin="16,0,7,0" FontSize="16" FontFamily="Andy"/>
                </StackPanel>
            </Grid>
        </DataTemplate>
    </Page.Resources>
    <!--
        This grid acts as a root panel for the page that defines two rows:
        * Row 0 contains the back button and page title
        * Row 1 contains the rest of the page layout
    -->
    <Grid x:Name="grd" Style="{StaticResource LayoutRootStyle}">
        <Grid.RowDefinitions>
            <RowDefinition Height="140"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <GridView
        x:Name="itemGridView"
        AutomationProperties.AutomationId="ItemsGridView"
        AutomationProperties.Name="Items"
        TabIndex="1"
        Grid.RowSpan="2"
        Padding="116,136,116,46"
        ItemsSource="{Binding Source={StaticResource itemsViewSource}}"
        ItemTemplate="{StaticResource DataTemplate1}"
        SelectionMode="None"
        IsSwipeEnabled="false"
        IsItemClickEnabled="True"
        ItemClick="ItemView_ItemClick">
            <GridView.Background>
                <ImageBrush ImageSource="Assets/bg4.jpg"/>
            </GridView.Background>
            <GridView.GroupStyle>
                <GroupStyle>
                    <GroupStyle.HeaderTemplate>
                        <DataTemplate>
                            <Grid Margin="1,0,0,6">
                                 <Button
                                    AutomationProperties.Name="Group Title"
                                    Style="{StaticResource TextPrimaryButtonStyle}" Content="" />
                            </Grid>
                        </DataTemplate>
                    </GroupStyle.HeaderTemplate>
                    <GroupStyle.Panel>
                        <ItemsPanelTemplate>
                            <VariableSizedWrapGrid Orientation="Vertical" Margin="0,0,80,0"/>
                        </ItemsPanelTemplate>
                    </GroupStyle.Panel>
                </GroupStyle>
            </GridView.GroupStyle>
        </GridView>
        <!-- Back button and page title -->
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <Button x:Name="backButton" Click="GoBack" IsEnabled="{Binding Frame.CanGoBack, ElementName=pageRoot}" Style="{StaticResource BackButtonStyle}"/>
            <TextBlock x:Name="pageTitle" Grid.Column="1" Style="{StaticResource PageHeaderTextStyle}" FontFamily="Buxton Sketch" FontSize="60" Foreground="#DEFFFFFF" Margin="0,0,30,44">
                <Run Foreground="#DE316191" Text="Merak"/>
                <Run FontSize="48" Text=" "/>
                <Run Foreground="#DEFDFDFD" Text="Edilen"/>
                <Run FontSize="48" Text=" "/>
                <Run Foreground="#DE3F6B97" Text="Şeyler"/>
            </TextBlock>
        </Grid>
        <VisualStateManager.VisualStateGroups>
            <!-- Visual states reflect the application's view state -->
            <VisualStateGroup x:Name="ApplicationViewStates">
                <VisualState x:Name="FullScreenLandscape"/>
                <VisualState x:Name="Filled"/>
                <!-- The entire page respects the narrower 100-pixel margin convention for portrait -->
                <VisualState x:Name="FullScreenPortrait">
                    <Storyboard>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PortraitBackButtonStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>
                <!-- The back button and title have different styles when snapped -->
                <VisualState x:Name="Snapped">
                    <Storyboard>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SnappedBackButtonStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="pageTitle" Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SnappedPageHeaderTextStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>
    </Grid>

有了这个，我可以用这个代码创建组；

public class Item
        {
            public string Title { get; set; }
            public string Description{ get; set; }
            public string Image { get; set; }
        }
        List<List<Item>> total = new List<List<Item>>();
        List<Item> lst = new List<Item>();
        public void AddGroups()
        {
            Item first= new Item();
            first.Title = "asdf";
            first.Description = "asdaf";
            first.Image = "aswdfa";
            lst.Add(first);
            total.Add(lst);
        }

有了这段代码，我可以添加没有标题文本的组，但我需要标题文本，没有它我什么都做不了。所以我试图创建另一个自定义类，并将这个新列表绑定到gridview。我试着创建一个这样的类，然后绑定这个类的列表，但它不起作用，显示了一个没有任何项目的空白屏幕；

public class grp
    {
        private List<Item> bilg;
        public grp(List<Item> bilg)
        {
            this.bilg = bilg;
        }
    }

第二节课可能完全错了，但我不知道。这是一个Windows应用商店应用程序，我正在使用xaml和c#。谢谢你的帮助。

tl；dr我正在试着制作一个网格视图，上面有组名。