如何使用Range对象读取VB.net中单词(*.doc)文件中复选框的值？

如何使用范围对象读取VB.net中单词(*.doc)文件中复选框的值？

这是我到目前为止:

Dim app As New Word.Application
Dim doc As Document
doc = app.Documents.Open("C:\myDoc.doc")
dim chkBox as Bookmark
chkBox = doc.Bookmarks("MyCheckbox")
Dim rng as Range
rng = chkBox.Range

其中"MyCheckbox"是word文档中复选框的书签.