FlowDocument is the only supported child element for a RichTextBox.

Important Note:

RichTextBox has built-in handling for the bubbling  MouseUp and MouseDown events. Consequently, custom event handlers that listen for MouseUp or MouseDown events from a RichTextBox will never be called. If you need to respond to these events, listen for the tunneling PreviewMouseUp and PreviewMouseDown events instead, or register the handlers with the HandledEventsToo argument (this latter option is only available through code). Do not mark the event handled unless you deliberately want to disable RichTextBox native handling of these events, and be aware that this has notable effects on the control's UI.

While RichTextBox supports copying and pasting of images, certain scenarios are currently unsupported and may not work properly. The following table summarizes these scenarios and expected results.

Pasting HTML content into a RichTextBox might result in unexpected behavior because RichTextBox uses RTF format rather then directly using HTML format.

Text always wraps in a RichTextBox. If you do not want text to wrap then set the PageWidth on the FlowDocument to be larger than the width of the RichTextBox. However, once the page width is reached the text still wraps.

Horizontally and vertically aligning content within a RichTextBox is done with the HorizontalContentAlignment and VerticalContentAlignment properties. Aligning the RichTextBox within the layout of the page is done with the HorizontalAlignment and VerticalAlignment properties.

Scrollbars are not visible on a RichTextBox by default. To make a scrollbar visible, set the VerticalScrollBarVisibility property to Visible or Auto.

Usually, the TextChanged event should be used to detect when the text in a TextBox or RichTextBox changes, rather then KeyDown as you might expect. For an example, see How to: Detect When Text in a TextBox Has Changed.

RichTextBox supports a variety of keyboard commands. For a list of keyboard commands, see EditingCommands.

The following example declares a RichTextBox that contains a simple FlowDocument.

<RichTextBox Name="richTB">
  <FlowDocument>
    <Paragraph>
      <Run>Paragraph 1</Run>
    </Paragraph>
    <Paragraph>
      <Run>Paragraph 2</Run>
    </Paragraph>
    <Paragraph>
      <Run>Paragraph 3</Run>
    </Paragraph>
  </FlowDocument>
</RichTextBox>

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Documents;
namespace SDKSample
{
    public partial class RichTextBoxExample : Page
    {
        public RichTextBoxExample()
        {

            StackPanel myStackPanel = new StackPanel();

            // Create a FlowDocument to contain content for the RichTextBox.
            FlowDocument myFlowDoc = new FlowDocument();

            // Add paragraphs to the FlowDocument.
            myFlowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 1")));
            myFlowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 2")));
            myFlowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 3")));
            RichTextBox myRichTextBox = new RichTextBox();

            // Add initial content to the RichTextBox.
            myRichTextBox.Document = myFlowDoc;

            myStackPanel.Children.Add(myRichTextBox);
            this.Content = myStackPanel;

        }
    }
}

More Code

Windows Vista

.NET Framework

Reference

Other Resources