VB代码设置系统默认打印机，调用API实现-VB code installed the system default printer, called API

用VB编写打印程序的时候，如果通过控制面板改变纸型和方向非常不方便。通过调用API函数可以方便的实现。-VB printing process used to prepare, if the control panel through the matrix and the direction of change is very inconvenient. By calling the API function can be easily realized.