从显示wpf中的图像的richtextbox复制表情符号“text”

I am looking for a good, clean way to enable copying of text from a richtextbox displaying emoticons. Think of skype, where you can select a chat and it will copy the emoticon images and convert them to their textual representations (smiley image to :) etc). I am using the MVVM pattern.I am looking for a good, clean way to enable co