string c1 = System.Drawing.ColorTranslator.ToHtml(System.Drawing.Color.Red);
// c1 = "#ff0000";或c1 = "Red";
System.Drawing.Color c2 = System.Drawing.ColorTranslator.FromHtml("#ff0000");
把系统的颜色KnownColor转换成Color
Color color=Color.FromKnownColor(KnownColor.Info);