本例只是演示了文件对话况的创建与使用，在“打开文件对话框”中，并未真正打开一个文件。在“保存文件对话框”中，也为真正保存一个文件。-In this case the dialogue is to demonstrate the status of document creation and use, in the " open file dialog box"　does not really open a file. At the " Save file dialog" , but also to really save a file.