Assuming you mean the HTML type RGB codes (called Hex codes, such as #FFCC66), use the ColorTranslator class:

System.Drawing.Color col = System.Drawing.ColorTranslator.FromHtml("#FFCC66");

If, however you are using an ARGB hex code, you can use the ColorConverter class from the System.Windows.Media namespace:

Color col = ColorConverter.ConvertFromString("#FFDFD991") as Color;
//or      = (Color) ColorConverter.ConvertFromString("#FFCC66") ;

If you don't want to use the ColorTranslator, you can do it in easily:

string colorcode = "#FFFFFF00";
int argb = Int32.Parse(colorcode.Replace("#", ""), NumberStyles.HexNumber);
Color clr = Color.FromArgb(argb);

The colorcode is just the hexadecimal representation of the ARGB value.

EDIT

If you need to use 4 values instead of a single integer, you can use this (combining several comments):

string colorcode = "#FFFFFF00";    
colorcode = colorcode.TrimStart('#');

Color col; // from System.Drawing or System.Windows.Media
if (colorcode.Length == 6)
    col = Color.FromArgb(255, // hardcoded opaque
                int.Parse(colorcode.Substring(0,2), NumberStyles.HexNumber),
                int.Parse(colorcode.Substring(2,2), NumberStyles.HexNumber),
                int.Parse(colorcode.Substring(4,2), NumberStyles.HexNumber));
else // assuming length of 8
    col = Color.FromArgb(
                int.Parse(colorcode.Substring(0, 2), NumberStyles.HexNumber),
                int.Parse(colorcode.Substring(2, 2), NumberStyles.HexNumber),
                int.Parse(colorcode.Substring(4, 2), NumberStyles.HexNumber),
                int.Parse(colorcode.Substring(6, 2), NumberStyles.HexNumber));

Note 1: NumberStyles is in System.Globalization.
Note 2: please provide your own error checking (colorcode should be a hexadecimal value of either 6 or 8 characters)

The three variants below give exactly the same color. The last one has the benefit of being highlighted in the Visual Studio 2010 IDE (maybe it's ReSharper that's doing it) with proper color.

var cc1 = System.Drawing.ColorTranslator.FromHtml("#479DEE");

var cc2 = System.Drawing.Color.FromArgb(0x479DEE);

var cc3 = System.Drawing.Color.FromArgb(0x47, 0x9D, 0xEE);

There is also this neat little extension method:

static class ExtensionMethods
{
    public static Color ToColor(this uint argb)
    {
        return Color.FromArgb((byte)((argb & -16777216)>> 0x18),      
                              (byte)((argb & 0xff0000)>> 0x10),   
                              (byte)((argb & 0xff00) >> 8),
                              (byte)(argb & 0xff));
    }
}

In use:

Color color = 0xFFDFD991.ToColor();

I needed to convert a HEX color code to a System.Drawing.Color, specifically a shade of Alice Blue as a background on a WPF form and found it took longer than expected to find the answer:

using System.Windows.Media;

--

System.Drawing.Color myColor = System.Drawing.ColorTranslator.FromHtml("#EFF3F7");
this.Background = new SolidColorBrush(System.Windows.Media.Color.FromArgb(myColor.A, myColor.R, myColor.G, myColor.B));

private Color FromHex(string hex)
{
    if (hex.StartsWith("#"))
        hex = hex.Substring(1);

    if (hex.Length != 6) throw new Exception("Color not valid");

    return Color.FromArgb(
        int.Parse(hex.Substring(0, 2), System.Globalization.NumberStyles.HexNumber),
        int.Parse(hex.Substring(2, 2), System.Globalization.NumberStyles.HexNumber),
        int.Parse(hex.Substring(4, 2), System.Globalization.NumberStyles.HexNumber));
}

You could use the following code:

Color color = System.Drawing.ColorTranslator.FromHtml("#FFDFD991");

If you want to do it with a Windows Store App, following by @Hans Kesting and @Jink answer:

    string colorcode = "#FFEEDDCC";
    int argb = Int32.Parse(colorcode.Replace("#", ""), NumberStyles.HexNumber);
    tData.DefaultData = Color.FromArgb((byte)((argb & -16777216) >> 0x18),
                          (byte)((argb & 0xff0000) >> 0x10),
                          (byte)((argb & 0xff00) >> 8),
                          (byte)(argb & 0xff));

in asp.net:

color_black = (Color)new ColorConverter().ConvertFromString("#FF76B3");

This post has become the goto for anyone trying to convert from a hex color code to a system color. Therefore, I thought I'd add a comprehensive solution that deals with both 6 digit (RGB) and 8 digit (ARGB) hex values.

By default, according to Microsoft, when converting from an RGB to ARGB value

The alpha value is implicitly 255 (fully opaque).

This means by adding FF to a 6 digit (RGB) hex color code it becomes an 8 digit ARGB hex color code. Therefore, a simple method can be created that handles both ARGB and RGB hex's and converts them to the appropriate Color struct.

    public static System.Drawing.Color GetColorFromHexValue(string hex)
    {
        string cleanHex = hex.Replace("0x", "").TrimStart('#');

        if (cleanHex.Length == 6)
        {
            //Affix fully opaque alpha hex value of FF (225)
            cleanHex = "FF" + cleanHex;
        }

        int argb;

        if (Int32.TryParse(cleanHex, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out argb))
        {
            return System.Drawing.Color.FromArgb(argb);
        }

        //If method hasn't returned a color yet, then there's a problem
        throw new ArgumentException("Invalid Hex value. Hex must be either an ARGB (8 digits) or RGB (6 digits)");

    }

This was inspired by Hans Kesting's answer.

For any Xamarin developers out there, you will need to

1. Specify the color type in order to prevent Cast exception from assuming you are talking about Xamarin.Forms.Color instead
2. Create an object of type ColorConverter

var conv = new System.Drawing.ColorConverter();
var color = (System.Drawing.Color)conv.ConvertFromString("#FF1D65AE");

You can see Silverlight/WPF sets ellipse with hexadecimal colour for using a hex value:

your_contorl.Color = DirectCast(ColorConverter.ConvertFromString("#D8E0A627"), Color)

There are many answers here already.

In short I support those that propose to use System.Drawing.ColorTranslator.

I get that some people want to avoid System.Windows.Media so there is the other solution, and since you want to have a System.Drawing.Color you should have a reference to System.Drawing already in your project.

So in short: Use the Framework if you can.

A more complete native solution

So, if for some reason you want to avoid System.Drawing.ColorTranslator and create your own implementation, you should at least make it respect the specifications

So this is a solution that does #RGB and #RGBA shorthand - and extended color definition

    public static Color ParseHtmlColor(string htmlColor) => Color.FromArgb(HtmlColorToArgb(htmlColor));

    public static int HtmlColorToArgb(string htmlColor, bool requireHexSpecified = false, int defaultAlpha = 0xFF)
    {

        if (string.IsNullOrEmpty(htmlColor))
        {
            throw new ArgumentNullException(nameof(htmlColor));
        }

        if (!htmlColor.StartsWith("#") && requireHexSpecified)
        {
            throw new ArgumentException($"Provided parameter '{htmlColor}' is not valid");
        }

        htmlColor = htmlColor.TrimStart('#');
        

        // int[] symbols 
        var symbolCount = htmlColor.Length;
        var value = int.Parse(htmlColor, System.Globalization.NumberStyles.HexNumber);
        switch (symbolCount)
        {
            case 3: // RGB short hand
            {
                return defaultAlpha << 24
                    | (value & 0xF)
                    | (value & 0xF) << 4
                    | (value & 0xF0) << 4
                    | (value & 0xF0) << 8
                    | (value & 0xF00) << 8
                    | (value & 0xF00) << 12
                    ;
            }
            case 4: // RGBA short hand
            {
                // Inline alpha swap
                return   (value & 0xF) << 24
                       | (value & 0xF) << 28
                       | (value & 0xF0) >> 4
                       | (value & 0xF0) 
                       | (value & 0xF00) 
                       | (value & 0xF00) << 4
                       | (value & 0xF000) << 4
                       | (value & 0xF000) << 8
                       ;
            }
            case 6: // RGB complete definition
            {
                return defaultAlpha << 24 | value;   
            }
            case 8: // RGBA complete definition
            {
                // Alpha swap
                return (value & 0xFF) << 24 | (value >> 8);
            }
            default:
                throw new FormatException("Invalid HTML Color");
        }
    }

If you for some reason don't want to use System.Globalization I'm sure you'll find a code snipped for parsing hex symbols.

Tests

    public static void TestColors()
    {
        foreach (var testCase in TestCases) TestColor(testCase);
    }

    static string[] TestCases = new string[] { 
        "111",
        "FFF", 
        "17A",
        "F52",
        "444F",
        "2348",
        "4320",
        "121212",
        "808080",
        "FFFFFF",
        "A0E0C0",
        "0A070B",
        "FFFFFFFF",
        "808080FF",
        "40807710"
    };

    public static void TestColor(string htmlColor)
    {
        Console.Write($" {htmlColor} -> ");
        var color = ParseHtmlColor(htmlColor);
        Console.WriteLine("0x" + color.ToArgb().ToString("X"));
    }

P.S.: Feel free to remove the paramters, they only intend to show how you could tweak the function to handle format errors and defaults.

P.P.S.: The error messages are not very descriptive at the moment

You can use the ColorConverter.ConvertFromString(string) method which converts your string (hexadecimal) to the color.

Example: (This works with ARGB, like "#FF1E1E1E".

Control.Background = new SolidColorBrush((Color)ColorConverter.ConvertFromString("#1E1E1E"));

WPF:

using System.Windows.Media;

//hex to color
Color color = (Color)ColorConverter.ConvertFromString("#7AFF7A7A");

//color to hex
string hexcolor = color.ToString();

Use

System.Drawing.Color.FromArgb(myHashCode);

I used ColorDialog in my project. ColorDialog sometimess return "Red","Fhushia" and sometimes return "fff000". I solved this problem like this maybe help someone.

        SolidBrush guideLineColor;
        if (inputColor.Any(c => char.IsDigit(c)))
        {
            string colorcode = inputColor;
            int argbInputColor = Int32.Parse(colorcode.Replace("#", ""), NumberStyles.HexNumber);
             guideLineColor = new SolidBrush(Color.FromArgb(argbInputColor));

        }
        else
        {
            Color col = Color.FromName(inputColor);
             guideLineColor = new SolidBrush(col);
        }

InputColor is the return value from ColorDialog.

Thanks everyone for answer this question.It's big help to me.

• XNA / Monogame (Microsoft.Xna.Framework.Color).
• Works for 6 or 8 (with alpha) character hexadecimal strings
• Probably better alternatives (bit masking/shifting) out there.

    using Microsoft.Xna.Framework;
    using System.Globalization;
    
    public static class ColorBuilder
    {
        public static Color FromHex(string color)
        {
            var hex = color.Replace("#", string.Empty);
            var h = NumberStyles.HexNumber;

            var r = int.Parse(hex.Substring(0, 2), h);
            var g = int.Parse(hex.Substring(2, 2), h);
            var b = int.Parse(hex.Substring(4, 2), h);
            var a = 255;

            if (hex.Length == 8)
            {
                a = int.Parse(hex.Substring(6, 2), h);
            }
 
            return new Color(r, g, b, a);
        }
    }
    
    //create a blue color
    var color = ColorBuilder.FromHex("#2733C5"); //or ColorBuilder.FromHex("2733C5");
    
    //create a blue color with 50% alpha
    var colorTrans = ColorBuilder.FromHex("#2733C580");

import UIKit

extension Color {

/// Initializes a `Color` from a HEX String (e.g.: `#1D2E3F`) and an optional alpha value.
/// - Parameters:
///   - hex: A String of a HEX representation of a color (format: `#1D2E3F`)
///   - alpha: A Double indicating the alpha value from `0.0` to `1.0`
init(hex: String, alpha: Double = 1.0) {
    let hex = hex.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
    var int: UInt64 = 0
    Scanner(string: hex).scanHexInt64(&int)
    self.init(hex: Int(int), alpha: alpha)
}

/// Initializes a `Color` from an Int (e.g.: `0x1D2E3F`)and an optional alpha value.
/// - Parameters:
///   - hex: An Int of a HEX representation of a color (format: `0x1D2E3F`)
///   - alpha: A Double indicating the alpha value from `0.0` to `1.0`
init(hex: Int, alpha: Double = 1.0) {
    let red = (hex >> 16) & 0xFF
    let green = (hex >> 8) & 0xFF
    let blue = hex & 0xFF
    self.init(.sRGB, red: Double(red) / 255, green: Double(green) / 255, blue: Double(blue) / 255, opacity: alpha)
}

/// Returns an Int representing the `Color` in hex format (e.g.: 0x112233)
var hex: Int {
    guard let components = cgColor?.components, components.count >= 3 else { return 0 }

    let red = lround((Double(components[0]) * 255.0)) << 16
    let green = lround((Double(components[1]) * 255.0)) << 8
    let blue = lround((Double(components[2]) * 255.0))

    return red | green | blue
}

/// Returns a HEX String representing the `Color` (e.g.: #112233)
var hexString: String {
    let color = self.hex

    return "#" + String(format: "%06x", color)
}

/// The alpha (opacity) component of the Color (0.0 - 1.0)
var alphaComponent: Double {
    NSColor(self).alphaComponent
}

}

extension NSColor {

/// Initializes a `NSColor` from a HEX String (e.g.: `#1D2E3F`) and an optional alpha value.
/// - Parameters:
///   - hex: A String of a HEX representation of a color (format: `#1D2E3F`)
///   - alpha: A Double indicating the alpha value from `0.0` to `1.0`
convenience init(hex: String, alpha: Double = 1.0) {
    let hex = hex.trimmingCharacters(in: .alphanumerics.inverted)
    var int: UInt64 = 0
    Scanner(string: hex).scanHexInt64(&int)
    self.init(hex: Int(int), alpha: alpha)
}

/// Initializes a `NSColor` from an Int  (e.g.: `0x1D2E3F`)and an optional alpha value.
/// - Parameters:
///   - hex: An Int of a HEX representation of a color (format: `0x1D2E3F`)
///   - alpha: A Double indicating the alpha value from `0.0` to `1.0`
convenience init(hex: Int, alpha: Double = 1.0) {
    let red = (hex >> 16) & 0xFF
    let green = (hex >> 8) & 0xFF
    let blue = hex & 0xFF
    self.init(srgbRed: Double(red) / 255, green: Double(green) / 255, blue: Double(blue) / 255, alpha: alpha)
}

/// Returns an Int representing the `NSColor` in hex format (e.g.: 0x112233)
var hex: Int {
    guard let components = cgColor.components, components.count >= 3 else { return 0 }

    let red = lround((Double(components[0]) * 255.0)) << 16
    let green = lround((Double(components[1]) * 255.0)) << 8
    let blue = lround((Double(components[2]) * 255.0))

    return red | green | blue
}

/// Returns a HEX String representing the `NSColor` (e.g.: #112233)
var hexString: String {
    let color = self.hex

    return "#" + String(format: "%06x", color)
}

}

If you mean HashCode as in .GetHashCode(), I'm afraid you can't go back. Hash functions are not bi-directional, you can go 'forward' only, not back.

Follow Oded's suggestion if you need to get the color based on the hexadecimal value of the color.