如何以编程方式检查MS Word 2007文档的任何文档属性是否已更改？

For example, I want the Title fields in the body and the page headers of the document to be updated automatically whenever the Title field in the document properties panel is changed. I know how to update the fields, but I want to know the name of the event that will tell me when the document properties have changed.For example, I want the Title fields in the bod