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FlowDocumentPageViewer SearchText and Highlighting

    Question

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    I am creating a  search and highlighting the text using the FlowDocumentPageViewer, something similar to the link given.

     

    http://kentb.blogspot.com/2009/06/search-and-highlight-text-in-arbitrary.html

     

     

    When I search for Tokens of string, (using a list of string) everything works fine and I get my rectangle applied appropriately. But I have two problems here,

     

    1.       When I change the pages of the FlowDocumentPageViewer, my Rectangular highlighted area remains the same and it is not sinking with the Text.

    2.       When I zoom in or zoom out of the FlowDocumentPageViewer, the text gets zoomed but the Highlight rectangle remains in the same position,

     

    Can you please help me in resolving this problem such that the rectangle gets applied to the Text itself. I am posing my application here. Please let me know still if you need further information.

     

    Best,

    Bala.

    <Window x:Class="Bingo1.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="325" Height="300"
        Title="Window1" DataContext="{Binding RelativeSource={RelativeSource Self}}" 
        SizeChanged="Window_SizeChanged">
        <Grid>
            <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="1.0*"/>
                <RowDefinition Height="9.0*"/>
            </Grid.RowDefinitions>
    
            <StackPanel Grid.Row="0" Orientation="Horizontal">
                <TextBox x:Name="_searchTextBox" Text="{Binding SearchText, UpdateSourceTrigger=PropertyChanged}" Width="200" Height="20" Margin="2"/>
                <Button x:Name="_searchButton" Height="{Binding Height, ElementName=_searchTextBox}" Width="50" Content="GO">
                    </Button>
                    <Button x:Name="_listItems" Height="{Binding Height, ElementName=_searchTextBox}" Width="50" Content="List"/>
                </StackPanel>
    
            <Grid Grid.Row="1">
                <FlowDocumentPageViewer>
                    <FlowDocument Foreground="Black" FontFamily="Arial">
                        <Paragraph FontSize="11">
                            The following details have been details from Amazon to match your initial query.Some of the returned values may have been empty, so have been ommitted from theresults shown here.Also where there have been more than one value returned viathe Amazon Details, these to have beenomitted for the sake of keeping things simplefor this small demo application. Simple is good,when trying to show how something works
                        </Paragraph>
                    </FlowDocument>
                </FlowDocumentPageViewer>
            </Grid>
                
            <ItemsControl ItemsSource="{Binding SearchRectangles}">
                <ItemsControl.ItemsPanel>
                    <ItemsPanelTemplate>
                        <Canvas/>
                    </ItemsPanelTemplate>
                </ItemsControl.ItemsPanel>
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                            <Rectangle Fill="#99FFFF00" Width="{Binding Width}"  Height="{Binding Height}"  Tag="{Binding Text}"  MouseDown="Rectangle_MouseDown">
                                <Rectangle.Style>
                                    <Style TargetType="{x:Type Rectangle}">
                                        <Style.Triggers>
                                            <Trigger Property="IsMouseOver" Value="True">
                                                <Setter Property="BitmapEffect">
                                                    <Setter.Value>
                                                        <OuterGlowBitmapEffect GlowColor="BurlyWood" GlowSize="7"/>
                                                    </Setter.Value>
                                                </Setter>
                                            </Trigger>
                                        </Style.Triggers>
                                    </Style>
                                </Rectangle.Style>
                                
                            </Rectangle>
                        </DataTemplate>
                </ItemsControl.ItemTemplate>
                <ItemsControl.ItemContainerStyle>
                    <Style>
                        <Setter Property="Canvas.Top" Value="{Binding Top}"/>
                        <Setter Property="Canvas.Left" Value="{Binding Left}"/>
                    </Style>
                </ItemsControl.ItemContainerStyle>
            </ItemsControl>
    
        </Grid>
        </Grid>
    </Window>
    
    
    C# Code:
    
      public partial class Window1 : Window
        {
            public static readonly DependencyProperty SearchTextProperty = DependencyProperty.Register("SearchText",
                                                    typeof(string),
                                                    typeof(Window1));
    
            public static readonly DependencyProperty SearchRectanglesProperty = DependencyProperty.Register("SearchRectangles",
                            typeof(ICollection<SearchRectangle>),
                            typeof(Window1));
    
    
    
            public IList<string> SearchTokens { get; set; }
    
    
            public Window1()
            {
                InitializeComponent();
    
                SearchRectangles = new ObservableCollection<SearchRectangle>();
    
                _searchButton.Click += delegate
                {
                    DoSearch();
                };
    
                _listItems.Click += delegate
                {
                    SearchTokens = new List<string>();
                    SearchTokens.Add("been");
                    SearchTokens.Add("Amazon");
                    SearchTokens.Add("following");              
                    DoSearch(SearchTokens);
    
                };
    
                _searchTextBox.KeyDown += delegate(object sender, KeyEventArgs e)
                {
                    if (e.Key == Key.Enter)
                    {
                        DoSearch();
                    }
                };
            }
    
    
            public void DoSearch(IList<string> searchTokens)
            {
                
                SearchRectangles.Clear();
    
                if (searchTokens == null)
                    return;
    
                foreach (string token in searchTokens)
                {
                    SearchText = token;
                    DoSearch();
                }
            }
    
            public string SearchText
            {
                get { return GetValue(SearchTextProperty) as string; }
                set { SetValue(SearchTextProperty, value); }
            }
    
            public ICollection<SearchRectangle> SearchRectangles
            {
                get { return GetValue(SearchRectanglesProperty) as ICollection<SearchRectangle>; }
                set { SetValue(SearchRectanglesProperty, value); }
            }
    
            private void DoSearch()
            {
                DoSearch(false);
            }
    
            private void DoSearch(bool clearExisting)
            {
                if( clearExisting == true ) 
                    SearchRectangles.Clear();
                if (SearchText.Length == 0)
                {
                    return;
                }
    
                DoSearch(this);
            }
    
            private void DoSearch(DependencyObject searchIn)
            {
                if (searchIn == null)
                {
                    return;
                }
    
                var contentHost = searchIn as IContentHost;
    
                if (contentHost != null)
                {
                    DoSearch(contentHost as UIElement, contentHost);
                }
                else
                {
                    var documentViewerBase = searchIn as DocumentViewerBase;
    
                    if (documentViewerBase != null)
                    {
                        //extract the content hosts from the document viewer
                        foreach (var pageView in documentViewerBase.PageViews)
                        {
                            contentHost = pageView.DocumentPage as IContentHost;
    
                            if (contentHost != null)
                            {
                                DoSearch(documentViewerBase, contentHost);
                            }
                        }
                    }
                }
    
                //recurse through children
                var childCount = VisualTreeHelper.GetChildrenCount(searchIn);
    
                for (var i = 0; i < childCount; ++i)
                {
                    DoSearch(VisualTreeHelper.GetChild(searchIn, i));
                }
            }
    
            private void DoSearch(UIElement uiHost, IContentHost contentHost)
            {
                if (uiHost == null)
                {
                    return;
                }
    
                var textBlock = contentHost as TextBlock;
    
                if (textBlock != null)
                {
                    //this has the side affect of converting any plain string content in the TextBlock into a hosted Run element
                    //that's bad in that it is unexpected, but good in that it allows us to access the hosted elements in a
                    //consistent fashion below, rather than special-casing TextBlocks with text only content
                    var contentStart = textBlock.ContentStart;
                }
    
                var hostedElements = contentHost.HostedElements;
    
                while (hostedElements.MoveNext())
                {
                    var run = hostedElements.Current as Run;
    
                    if (run != null && !string.IsNullOrEmpty(run.Text))
                    {
                        ApplyHighlighting(run.Text, delegate(int start, int length)
                        {
                            var textPointer = run.ContentStart;
                            textPointer = textPointer.GetPositionAtOffset(start, LogicalDirection.Forward);
                            var leftRectangle = textPointer.GetCharacterRect(LogicalDirection.Forward);
                            textPointer = textPointer.GetPositionAtOffset(length, LogicalDirection.Forward);
                            var rightRectangle = textPointer.GetCharacterRect(LogicalDirection.Backward);
                            var rect = new Rect(leftRectangle.TopLeft, rightRectangle.BottomRight);
                            var translatedPoint = uiHost.TranslatePoint(new Point(0, 0), null);
                            rect.Offset(translatedPoint.X, translatedPoint.Y);
                            return rect;
                        });
    
                    }
                }
            }
    
            private void ApplyHighlighting(string text, Func<int, int, Rect> getRectHandler)
            {
                var currentIndex = 0;
    
                while (true)
                {
                    var index = text.IndexOf(SearchText, currentIndex, StringComparison.CurrentCultureIgnoreCase);
    
                    if (index == -1)
                    {
                        return;
                    }
    
                    var rect = getRectHandler(index, SearchText.Length);
    
                    if (rect != Rect.Empty)
                    {
                        SearchRectangles.Add(new SearchRectangle(rect.Top, rect.Left, rect.Width, rect.Height,SearchText));
                    }
    
                    currentIndex = index + SearchText.Length;
                }
            }
    
            private void Rectangle_MouseDown(object sender, MouseEventArgs e)
            {
                Rectangle r = sender as Rectangle;
                MessageBox.Show(r.Tag.ToString());
            }
    
            private void FlowDocumentPageViewer_PageViewsChanged(object sender, EventArgs e)
            {
    
            }
    
            private void Window_SizeChanged(object sender, SizeChangedEventArgs e)
            {
                DoSearch(SearchTokens);
            }
    
        }
    
        public class SearchRectangle
        {
            private readonly double _top;
            private readonly double _left;
            private readonly double _width;
            private readonly double _height;
            private readonly string _text;
    
            public SearchRectangle(double top, double left, double width, double height,string text)
            {
                _top = top;
                _left = left;
                _width = width;
                _height = height;
                _text = text;
    
            }
    
            public string Text
            {
                get { return _text; }
            }
    
            public double Top
            {
                get { return _top; }
            }
    
            public double Left
            {
                get { return _left; }
            }
    
            public double Width
            {
                get { return _width; }
            }
    
            public double Height
            {
                get { return _height; }
            }
        }
    
    
    
    
    
    

     

     

     

    Wednesday, November 18, 2009 12:41 PM

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