VC中当窗口大小变化时，调整控件位置和尺寸的类。 外国人写的类。-When the window size in VC changes, the adjustment controls the location and size category. Foreigners to write the class.

These constants are also useful for user-level apps (e.g., VC resizing).

自动改变控件尺寸源代码，vc简单demo(change control size when window is resizing automatic)