窗口透明度(Alpha)控制，通过调用API控制窗口的透明度，可以用于实现特殊视觉效果的窗体。用法简单，VB6即可实现。-Window transparency (Alpha) control, by calling the API to control the transparency of the window, can be used to achieve special visual effects of the form. Use of simple, VB6 can be reali