Control阴影，C#给窗体上的控件加上阴影效果，让显示的元素更有视觉效果，初级代码，还有很多地方需要完善的，新手可参考按钮渐变绘制、圆角的处理等相关技巧。-Control shadows, C# controls on the form to add a shadow effect, so that the elements displayed more visual effects, the primary code, there are many areas that need impr