in the absence of documentation, depending on the structure for the use of print...

代码说明：

在没有文档、视结构的情况下使用打印预览，比较经典的程序，可以学习windows底层程序编写技巧.-in the absence of documentation, depending on the structure for the use of print preview, compared to the classic procedure, we can learn from the bottom windows programming skills.