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c#wpftextbox

Automatic highlighting a part of the text in a TextBox or RichTextBox

Is it possible to highlight a part of a text without selecting this part of the text preferably with a different color in Textbox or Rich TextBox? In fact, I mean, a part of the text is highlighted by another color differing from the color assigned for text selection. To clarify, I have attached an image showing this behavior. (The image is from a website, not WPF). The bold and dark green part is a text which is just highlighted, and the gray region is a selected part. enter image description here

Solution

  • Using the RichTextBox element allows for more styling options which, to my knowledge, aren't available for the regular TextBox element.

    Here is an approach that I have created:

    // Generate example content
FlowDocument doc = new FlowDocument();

Run runStart = new Run("This is an example of ");
Run runHighlight = new Run("text highlighting in WPF");
Run runEnd = new Run(" using the RichTextBox element.");

// Apply highlight style
runHighlight.FontWeight = FontWeights.Bold;
runHighlight.Background = Brushes.LightGreen;

// Create paragraph
Paragraph paragraph = new Paragraph();
paragraph.Inlines.Add(runStart);
paragraph.Inlines.Add(runHighlight);
paragraph.Inlines.Add(runEnd);

// Add the paragraph to the FlowDocument
doc.Blocks.Add(paragraph);

// Apply to RichTextBox
YourRichTextBoxHere.Document = doc;

    View Screenshot