Detect if a RichTextBox is empty

Question

What is the best way to detect if a WPF RichTextBox/FlowDocument is empty?

The following works if only text is present in the document. Not if it contains UIElement\'s

Answer 1

The answer above works if you don't put anything into the RTB. However, if you simply delete the contents, the RTB tends to return a single, empty paragraph, not a completely empty string. So, this is more reliable in such cases:

string text = new TextRange(Document.ContentStart, Document.ContentEnd).Text;
return !String.IsNullOrWhiteSpace(text);

This only applies to textual contents, of course.