一个封装好的类（RichText Builder (StringBuilder for RTF)．可以将Rich Text控件中的内容直接保存为ＲＴＦ格式文件．,A good type of package (RichText Builder (StringBuilder for RTF). Could be in the Rich Text content controls directly saved as RTF files.

richtextbox例子，表情，字体格式设置-richtextbox example, facial expressions, font formatting