html页面颜色名称和颜色值转换

  public static string ToHtmlColor(string colorName)        {

            try

            {

                if (colorName.StartsWith("#"))

                    colorName = colorName.Replace("#", string.Empty);

                int v = int.Parse(colorName, System.Globalization.NumberStyles.HexNumber);

                Color col = Color.FromArgb

               (

                     Convert.ToByte((v >> 24) & 255),

                     Convert.ToByte((v >> 16) & 255),

                     Convert.ToByte((v >> 8) & 255),

                     Convert.ToByte((v >> 0) & 255)

                );

                int alpha = col.A;

                var red = Convert.ToString(col.R, 16); ;

                var green = Convert.ToString(col.G, 16);

                var blue = Convert.ToString(col.B, 16);

                return string.Format("#{0}{1}{2}", red, green, blue);

            }

            catch

            {

                return "black";

            }

        }

       public static String ColorToStr(System.Drawing.Color color)

        {

            try

            {

                string color_s = System.Drawing.ColorTranslator.ToHtml(color);

                color_s = color_s.Substring(1, color_s.Length - 1);

                return "#" + Convert.ToString(Convert.ToInt32(color_s, 16) + 40000, 16);

            }

            catch

            {

                return "black";

            }

        }