本程序主要演示如何在对话框中使用只有在文档-视图模型中才能使用的打印预览功能，其实本程序也使用了一个没有文档类的文档-视图结构来间接完成打印预工作的，但我们在使用时基本感觉不到它的存在。

在实际使用中可将文档-视图部分编制成扩展动态链接库，我就是这样做的，编制打印程序时使用起来非常方便。-The main demonstration of the procedures used in the dialog box only when the document- View the model in order to use the Print Preview feature, in fact, this procedure does not use a document type of document- view architecture to indirectly advance the completion of the work of printing, but we In the basic sense of when not to use it. Can be used in the actual document- view into the expansion of part of the preparation of a dynamic link library, what I did, and the preparation of printing process is very convenient to use.