How can I detect Hyperlink Text Change?

Question

I have this richtextbox with some hyperlinks, these hyperlinks allows users to change the text of it, and I need to make further actions when the text of it is changed. The hyperlink itself has nothing special, just like below:

Hyperlink link = new Hyperlink();
Run run = new Run("haha");
link.Inlines.Add(run);

When the users type within the link, I would like to detect that user action and make further moves, something like:

link.textchanged += myHandler;

So far, I tried to use textBox as the inline of the hyperlink, though it works, but there are so many downsides such as it automatically switch to the next line when there's no enough space.

I also tried to use textrange.changed method, but it did not work.

Thanks!