带格式分离两个RichEditControl的文本

using( RichEditControl selector = new RichEditControl() {
RtfText = richTextFromHtml
} ) {
DocumentRange rangeBlockOne = selector.Document.CreateRange( ,  );
DocumentRange rangeBlockTwo = selector.Document.CreateRange( ,  );
richTextBlockOne = selector.Document.GetRtfText( rangeBlockOne );
richTextBlockTwo = selector.Document.GetRtfText( rangeBlockTwo );
}