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

H.B.'s answer isn't useful if you need to distinguish between images and whitespace. You can use something like this answer to check for images.

bool IsEmpty(Document document)
{
    string text = new TextRange(Document.ContentStart, Document.ContentEnd).Text;
    if (string.IsNullOrWhiteSpace(text) == false)
        return false;
    else
    {
        if (document.Blocks.OfType()
            .Select(c => c.Child).OfType()
            .Any())
        return false;
    }
    return true;
}

This seems laborious, and still probably isn't correct for all scenarios. But I couldn't find any better way.