[ACCEPTED]-Convert .Net Color Objects to HEX codes and Back-system.drawing.color

Something like :

Color color = Color.Red;
string colorString = string.Format("#{0:X2}{1:X2}{2:X2}",
    color.R, color.G, color.B);

Doing it the other way is 4 a little more complex as #F00 is a valid 3 html color (meaning full red) but it is 2 still doable using regex, here is a small 1 sample class :

using System;
using System.Diagnostics;
using System.Drawing;
using System.Text.RegularExpressions;
using System.Collections.Generic;

public static class HtmlColors
{
    public static string ToHtmlHexadecimal(this Color color)
    {
        return string.Format("#{0:X2}{1:X2}{2:X2}", color.R, color.G, color.B);
    }

    static Regex htmlColorRegex = new Regex(
        @"^#((?'R'[0-9a-f]{2})(?'G'[0-9a-f]{2})(?'B'[0-9a-f]{2}))"
        + @"|((?'R'[0-9a-f])(?'G'[0-9a-f])(?'B'[0-9a-f]))$",
        RegexOptions.Compiled | RegexOptions.IgnoreCase);

    public static Color FromHtmlHexadecimal(string colorString)
    {
        if (colorString == null)
        {
            throw new ArgumentNullException("colorString");
        }

        var match = htmlColorRegex.Match(colorString);
        if (!match.Success)
        {
            var msg = "The string \"{0}\" doesn't represent"
            msg += "a valid HTML hexadecimal color";
            msg = string.Format(msg, colorString);

            throw new ArgumentException(msg,
                "colorString");
        }

        return Color.FromArgb(
            ColorComponentToValue(match.Groups["R"].Value),
            ColorComponentToValue(match.Groups["G"].Value),
            ColorComponentToValue(match.Groups["B"].Value));
    }

    static int ColorComponentToValue(string component)
    {
        Debug.Assert(component != null);
        Debug.Assert(component.Length > 0);
        Debug.Assert(component.Length <= 2);

        if (component.Length == 1)
        {
            component += component;
        }

        return int.Parse(component,
            System.Globalization.NumberStyles.HexNumber);
    }
}

Usage :

// Display #FF0000
Console.WriteLine(Color.Red.ToHtmlHexadecimal());

// Display #00FF00
Console.WriteLine(HtmlColors.FromHtmlHexadecimal("#0F0").ToHtmlHexadecimal());

// Display #FAF0FE
Console.WriteLine(HtmlColors.FromHtmlHexadecimal("#FAF0FE").ToHtmlHexadecimal());

"White" is a valid HTML color. Please 9 see ColorTranslator.ToHtml:

This method translates a Color structure 8 to a string representation of an HTML 7 color. This is the commonly used name 6 of a color, such as "Red", "Blue", or 5 "Green", and not string representation 4 of a numeric color value, such as "FF33AA".

If 3 your color cannot be mapped to a HTML color 2 string this method will return the valid 1 hex for the color. See this example:

using System;
using System.Drawing;

class Program
{
    static void Main()
    {
        Console.WriteLine(ColorTranslator.ToHtml(Color.White));
        Console.WriteLine(ColorTranslator.ToHtml(Color.FromArgb(32,67,89)));
    }
}

If you will convert the color back with 11 {ColorTranslator.FromHTML}, 'White' is a 10 valid string for a HTML color. But I've 9 found that this implementation needs a # symbol 8 before the string that represents the color 7 if it isn't common (for example, it works 6 with White, and #FFFFFF, but it doesn't 5 with #White or FFFFFF). So I tried putting 4 the conversion inside a try/catch block, made 3 the conversion adding '#'to the string and 2 if it threw an exception then I caught it 1 and made the conversion without #.

I have written my own .net extension for 2 simple converting from hex to integer and 1 integer(ARGB) to color and vise versa:

Imports System.Drawing
Imports System.Runtime.CompilerServices

Public Module ColorsExt

    Private Sub example_for_usage()
        Dim hex As String
        Dim c As Color = Color.Red
        hex = c.ToHexString() 'Converts color to hexadecimal string'
        c = hex.ToIntegerFromHex().ToColor() 'Gets Integer value from the hex string and simply convert it to Color()'
    End Sub

    <Extension> _
    Public Function ToColor(ByVal argb As Integer) As Color
        Return Color.FromArgb(argb)
    End Function

    <Extension> _
    Public Function ToIntegerFromHex(ByVal argb_hex_string As String) As Integer
        Return Int("&H" + argb_hex_string)
    End Function

    <Extension> _
    Public Function ToHexString(ByVal c As Color) As String
        Return String.Format("{0:X2}{1:X2}{2:X2}{3:X2}", c.A, c.R, c.G, c.B)
    End Function

    <Extension> _
    Public Sub FromHexString(ByVal c As Color, ByVal hex As String)
        c = hex.ToIntegerFromHex().ToColor()
    End Sub

    <Extension> _
    Public Function ToHexString(ByVal c As Integer) As String
        Return String.Format("{0:X8}", c)
    End Function

    <Extension> _
    Public Function ToArgb(ByVal c As Color) As Integer
        Return (c.A * &HFF0000) + (c.R * &HFF00) + (c.G * &HFF) + (c.B)
    End Function

End Module