How to bind a WPF hyperlink in a richtextbox to a command?

Question

With the MVVM pattern, how does one go about dynamically binding an ICommand to the click event of a hyperlink inside of a RichTextBox?

Answer 1

It's a few steps to get there, but you can do it.

1. You have to use a bindable rich text box, rather than the one that comes with WPF which is not something you can bind. Details here: http://michaelsync.net/2009/06/09/bindable-wpf-richtext-editor-with-xamlhtml-convertor

2. Once you have that, you'll have a Rich Text Editor that you can bind to a FlowDocument in your ViewModel.

3. When your FlowDocument is created, hookup a handler for the Hyperlink.ClickEvent in your ViewModel:

Here's the call that adds the handler to the FlowDoc

TheDocument.AddHandler(Hyperlink.ClickEvent, 
    new RoutedEventHandler(HandleHyperlinkClick));


//Here's the handler definition    
private void HandleHyperlinkClick(object sender, RoutedEventArgs args)
{
    Hyperlink link = args.Source as Hyperlink;
    //...
}

This is the only thing I've ever seen done. FlowDocuments are a little strange because they are sort of a data type and sort of a visual element so in some sense it feels wrong to have it reside in your ViewModel, but this is the way to go.

Answer 2

You find a lot scenarios where it is not possible to use wpf data binding. In these scenarios you can create a new control (e.g. inherit from RichTextBox) and provide the missing dependency properties so you can use data binding.

However, creating a new control to handle simple scenarios is inefficient. It's not forbidden to implement code in the View's code behind file and this makes often more sense than creating a new control.

A concrete example how this can be done is shown in the ViewModel sample of the project:

WPF Application Framework (WAF)

http://waf.codeplex.com