How to do thumbnail navigation using PDF Viewer?

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:ThumbnailView"
             xmlns:sfpdfviewer="clr-namespace:Syncfusion.SfPdfViewer.XForms;assembly=Syncfusion.SfPdfViewer.XForms"
             xmlns:syncfusion="clr-namespace:Syncfusion.ListView.XForms;assembly=Syncfusion.SfListView.XForms"
             x:Class="HelloWorld.MainPage">
 
<ContentPage.Resources>
        <ResourceDictionary>
            <local:ByteImageConverter x:Key="ByteImgConverter"/>
        </ResourceDictionary>
</ContentPage.Resources>
 
<ContentPage.BindingContext>
        <local:PdfViewerViewModel/>
</ContentPage.BindingContext>
 
 <Grid x:Name="mainGrid" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" RowSpacing="0">
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="90" />
        </Grid.RowDefinitions>
 
        <Grid x:Name="pdfViewerGrid" Grid.Row="0" >
            <sfpdfviewer:SfPdfViewer x:Name="pdfViewerControl" InputFileStream="{Binding PdfDocumentStream}" />
        </Grid>
 
        <Grid x:Name="thumbnailView" Grid.Row="1">
            <syncfusion:SfListView x:Name="listView" ItemsSource="{Binding ThumbnailInfoCollection}" ItemTapped="ListView_OnItemTapped" Orientation="Horizontal">
                <syncfusion:SfListView.ItemTemplate>
                    <DataTemplate x:Name="ItemTemplate"  x:Key="ItemTemplate" >
                        <ViewCell>
                            <ViewCell.View>
                                <Grid x:Name="grid" RowSpacing="5">
                                    <Image Source="{Binding ThumbnailImage, Converter={StaticResource ByteImgConverter}}"
                                           VerticalOptions="Fill"
                                           HorizontalOptions="Fill"
                                           HeightRequest="90">
                                    </Image>
                                </Grid>
                            </ViewCell.View>
                        </ViewCell>
                    </DataTemplate>
                </syncfusion:SfListView.ItemTemplate>
            </syncfusion:SfListView>
        </Grid>
    </Grid>
</ContentPage>
 

private PdfViewerViewModel viewModel;
 
public MainPage()
{
        InitializeComponent();
        pdfViewerControl.DocumentLoaded += PdfViewerControl_DocumentLoaded;
        pdfViewerControl.DocumentSaveInitiated += PdfViewerControl_DocumentSaved;
}
 
/// <summary>
/// Event triggered once the document has been loaded
/// </summary>
private void PdfViewerControl_DocumentLoaded(object sender, EventArgs args)
{
        viewModel = this.BindingContext as PdfViewerViewModel;
        //Convert the PDF pages into stream.
        Stream[] exportedImages = pdfViewerControl.ExportAsImage(0, pdfViewerControl.PageCount - 1, 0.1f);
        ConvertStreamToImageSource(exportedImages);
        viewModel.UpdateImages();
}
 
/// <summary>
/// Converts stream into image.
/// </summary>
private void ConvertStreamToImageSource(Stream[] imageStreams)
{
        foreach (Stream imageStream in imageStreams)
        {
             imageStream.Position = 0;
             byte[] bytes = ReadBytes(imageStream);
             viewModel.ThumbnailBytes.Add(bytes);
        }
}
 
private byte[] ReadBytes(Stream input)
{
         byte[] buffer = new byte[16 * 1024];
         using (MemoryStream ms = new MemoryStream())
         {
                int read;
                while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
                {
                    ms.Write(buffer, 0, read);
                }
                return ms.ToArray();
          }
}
 
/// <summary>
/// Event triggered once the document has been saved
/// </summary>
private void PdfViewerControl_DocumentSaved(object sender, DocumentSaveInitiatedEventArgs args)
{
         string filePath = DependencyService.Get<ISave>().Save(args.SaveStream as MemoryStream);
         string message = "The PDF has been saved to " + filePath;
         DependencyService.Get<IAlertView>().Show(message);
}
 
/// <summary>
/// Event triggered when select the image items in the list view collection.
/// </summary>
private void ListView_OnItemTapped(object sender, ItemTappedEventArgs e)
{
       if (e.ItemData is ThumbnailInfo)
       {
             int pageNumberToNavigate = (e.ItemData as ThumbnailInfo).PageNumber;
             pdfViewerControl.GoToPage(pageNumberToNavigate);
       }
}