WPF RichTextBox

If you want a WPF RichTextBox where URLs in the text are automatically clickable links. By default, RichTextBox just treats text as plain content or FlowDocument content — it won’t automatically make URLs clickable. You have to either detect URLs and convert them to Hyperlink elements, or handle mouse clicks manually.

Here’s how to do it step by step.

Step 1: Use a RichTextBox with a FlowDocument

Important: IsDocumentEnabled="True" allows Hyperlink elements inside the RichTextBox to be clickable.

Step 2: Add text with URLs and convert them to Hyperlink programmatically

using System.Text.RegularExpressions;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Input;

namespace ClickableUrlExample
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            AddTextWithClickableUrls("Visit https://www.example.com or http://google.com for more info.");
        }

        private void AddTextWithClickableUrls(string text)
        {
            var doc = new FlowDocument();
            var paragraph = new Paragraph();

            // Regex to find URLs
            var urlPattern = @"(http[s]?://[^\s]+)";
            var parts = Regex.Split(text, urlPattern);

            foreach (var part in parts)
            {
                if (Regex.IsMatch(part, urlPattern))
                {
                    // Create a clickable hyperlink
                    var hyperlink = new Hyperlink(new Run(part))
                    {
                        NavigateUri = new System.Uri(part)
                    };
                    hyperlink.RequestNavigate += Hyperlink_RequestNavigate;
                    paragraph.Inlines.Add(hyperlink);
                }
                else
                {
                    paragraph.Inlines.Add(new Run(part));
                }
            }

            doc.Blocks.Add(paragraph);
            richTextBox.Document = doc;
        }

        private void Hyperlink_RequestNavigate(object sender, System.Windows.Navigation.RequestNavigateEventArgs e)
        {
            // Open the link in default browser
            System.Diagnostics.Process.Start(new System.Diagnostics.ProcessStartInfo(e.Uri.AbsoluteUri) { UseShellExecute = true });
            e.Handled = true;
        }
    }
}

Step 3: Explanation

• IsDocumentEnabled = true is crucial for hyperlinks to work.

• The Regex detects URLs in the text.

• Each URL is replaced with a Hyperlink element.

• RequestNavigate event handles the click and opens the URL in the default browser.

• Non-URL text is added as a normal Run element.

Optional Enhancements

1. Automatically detect URLs while typing: Attach a TextChanged handler and re-parse the text to add hyperlinks.

2. Styling hyperlinks: You can set Foreground color, underline style, etc.

hyperlink.Foreground = Brushes.Blue;
hyperlink.TextDecorations = TextDecorations.Underline;

3. Support email links: Extend the regex to include mailto:.