C#GDI绘制渐变线条，可用于添加阴…

Color c=Color.FromArgb(255,123,123,123) 参数分别是 A(透明度) R,G,B 红绿蓝

              Pen[] p1 = new Pen[4];

               int TranparentLevel = 40;

            for (int i = 0; i < p1.Length; i++)  

            {

                p1[i] = new Pen(Color.FromArgb(225 - Gradient * i, 255, 255, 255), 1);

                e.Graphics.DrawLine(p1[i], i, i, this.Width - i, i);

            }