常遇到某些程序只能发送到默认打印机打印，有时需要切换打印打印不同纸张，本程序实现两个2个打印机之间切换。 初学者写的比较简单，算是给大家提个思路吧-Often encounter some programs can only be sent to the default printer, and sometimes need to switch different paper Print, the program switches between two two printers. Be