How can I get a TextPointer with a mouse in a FlowDocument

Question

I would like to get the word that the user clicked in the FlowDocument.

I am currently adding an event handler for each run in the document and iterating through TextPointers in Run, which was clicked, calling GetCharacterRect () on each of them and checking if the rectangle contains this point.

However, when a click occurs near the end of a long run, it takes> 10 seconds.

Is there a more efficient method?

Answer 1

I would say that the easiest way is to use automation interfaces:

using System.Windows.Automation.Peers;
using System.Windows.Automation.Provider;

FlowDocument flowDocument = ...;
Point point = ...;

var peer = new DocumentAutomationPeer(flowDocument);
var textProvider = (ITextProvider)peer.GetPattern(PatternInterface.Text);
var rangeProvider = textProvider.RangeFromPoint(point);

ITextProvider UIAutomationProvider. , . UIAutomationTypes .

, , FlowDocument:

var peer = new DocumentAutomationPeer(flowDocument);
var peer = new DocumentAutomationPeer(textBlock);
var peer = new DocumentAutomationPeer(flowDocumentScrollViewer);
var peer = new TextBoxAutomationPeer(textBox);
var peer = new RichTextBoxAutomationPeer(richTextBox);

, , ITextRangeProvider TextPointer , .

ScreenPointToTextPointer . , :

private void Window_MouseMove(object sender, MouseEventArgs e)
{
  var document = this.Viewer.Document;
  var screenPoint = PointToScreen(e.GetPosition(this));

  TextPointer pointer = document.ScreenPointToTextPointer(screenPoint);

  new TextRange(document.ContentStart, pointer).ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Bold);
  new TextRange(pointer, document.ContentEnd).ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Normal);
}

:

using System.Windows.Automation.Peers;
using System.Windows.Automation.Provider;
using System.Windows.Automation.Text;

public static class DocumentExtensions
{
  // Point is specified relative to the given visual
  public static TextPointer ScreenPointToTextPointer(this FlowDocument document, Point screenPoint)
  {
    // Get text before point using automation
    var peer = new DocumentAutomationPeer(document);
    var textProvider = (ITextProvider)peer.GetPattern(PatternInterface.Text);
    var rangeProvider = textProvider.RangeFromPoint(screenPoint);
    rangeProvider.MoveEndpointByUnit(TextPatternRangeEndpoint.Start, TextUnit.Document, 1);
    int charsBeforePoint = rangeProvider.GetText(int.MaxValue).Length;

    // Find the pointer that corresponds to the TextPointer
    var pointer = document.ContentStart.GetPositionAtOffset(charsBeforePoint);

    // Adjust for difference between "text offset" and actual number of characters before pointer
    for(int i=0; i<10; i++)  // Limit to 10 adjustments
    {
      int error = charsBeforePoint - new TextRange(document.ContentStart, pointer).Text.Length;
      if(error==0) break;
      pointer = pointer.GetPositionAtOffset(error);
    }
    return pointer;
  }

}

PointToScreen MouseMove, .

Answer 2

FlowDocument RichTextBox, GetPositionFromPoint() TextPointer.

Answer 3

Click , PreviewMouseLeftButtonUp /, Run, .

RangeFromPoint,

PointToScreen, .