Any way to search two FlowDocuments at the same time?

Question

I have two FlowDocuments side by side in two different stack panels. I need a way to search both the documents at the same time for a particular text. As in if I type "car" in the text box both flow document reader should and search for and scroll to the next instance of "car" if there is one. Is there any way to achieve this? The FlowDocument is inside a FlowDocumentReader.

Answer 1

Here I have a basic WPF XAML layout, with 2 FlowDocumentReaders as you specified. I have a search TextBox and am going to run the code behind whenever the search text changes:

<Window x:Class="WpfFlowTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfFlowTest"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">

  <DockPanel>
    <!-- Search Box -->
    <TextBox Name="SearchTextBox" DockPanel.Dock="Top" TextChanged="TextBox_TextChanged"/>

    <!-- 2 Flow Readers -->
    <UniformGrid Columns="2">
      <FlowDocumentReader Name="FlowReader1">
        <FlowDocument>
          <Paragraph>
            Here is some text in panel number 1
          </Paragraph>
        </FlowDocument>
      </FlowDocumentReader>

      <FlowDocumentReader Name="FlowReader2">
        <FlowDocument>
          <Paragraph>
            Here is some more text in panel number 2
          </Paragraph>
        </FlowDocument>
      </FlowDocumentReader>
    </UniformGrid>
  </DockPanel>
</Window>

In the MainWindow.xaml.cs file I have this code which will highlight the flow document where the text matches what you typed in:

private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            var searchText = SearchTextBox.Text;

            DoSearch(FlowReader1, searchText);
            DoSearch(FlowReader2, searchText);
        }

        private void DoSearch(FlowDocumentReader reader, string search)
        {
            var doc = reader.Document;
            var text = doc.ContentStart;

            var docRange = new TextRange(doc.ContentStart, doc.ContentEnd);
            docRange.ClearAllProperties();

            while (true)
            {
                var next = text.GetNextContextPosition(LogicalDirection.Forward);
                if (next == null)
                {
                    break;
                }

                var txt = new TextRange(text, next);

                int indx = txt.Text.IndexOf(search);
                if (indx > 0)
                {
                    var sta = text.GetPositionAtOffset(indx);
                    var end = text.GetPositionAtOffset(indx + search.Length);
                    var textR = new TextRange(sta, end);

                    // Make it yellow
                    textR.ApplyPropertyValue(TextElement.BackgroundProperty, new SolidColorBrush(Colors.Yellow));
                }
                text = next;
            }

        }

Answer 2

I've posted my slight modification for people who want to scroll.

private void TextBox_TextChanged(object sender, EventArgs e)
        {
            var searchText = SearchTextBox.Text;

            if (searchText != null || searchText != "")
            {
                var FlowReader1 = (FlowDocumentReader)diffResults.Children[0];
                var FlowReader2 = (FlowDocumentReader)oldResults.Children[0];

                DoSearch(FlowReader1, searchText);
                DoSearch(FlowReader2, searchText);
            }
        }

        private void DoSearch(FlowDocumentReader reader, string search)
        {
            bool toScroll = true;
            var doc = reader.Document;
            var text = doc.ContentStart;

            var docRange = new TextRange(doc.ContentStart, doc.ContentEnd);
            docRange.ClearAllProperties();

            while (true)
            {
                var next = text.GetNextContextPosition(LogicalDirection.Forward);
                if (next == null)
                {
                    break;
                }

                var txt = new TextRange(text, next);

                int indx = txt.Text.IndexOf(search);
                if (indx >= 0)
                {   
                    var sta = text.GetPositionAtOffset(indx);
                    var end = text.GetPositionAtOffset(indx + search.Length);
                    if (end == null)
                    {
                        end = text.GetPositionAtOffset(indx + 1);
                    }
                    var textR = new TextRange(sta, end);

                    if (toScroll && text.Paragraph != null)
                    {
                        text.Paragraph.BringIntoView();
                        toScroll = false;
                    }
                    // Make it yellow
                    textR.ApplyPropertyValue(TextElement.BackgroundProperty, new SolidColorBrush(Colors.Yellow));
                }
                text = next;
            }