Convert Hex String to .NET Color
By
Steve on
Tuesday, January 09, 2007
Updated
Friday, April 22, 2016
Viewed
161,822 times. (
1 times today.)
Summary
For a long time I had a fairly complicated way of converting a hex string like #F782AB to a .NET color object. Since then some of you have informed me of a much easier way. I'll show you the easy way first and then include the longer method below.
string xCol = "#FF00DD";
Color c = System.Drawing.ColorTranslator.FromHtml(xCol);
Simple, right? Well, before I learned about that little trick here are some hoops and barrels I jumped through to make this happen. Maybe there's something useful in there from a purely tautological point of view. Not that I know what tautological means...that is to say, not that I know the definition of that particular word...
Example: How to use the conversion method
public void TestHexStringToColor()
{
// invent some hex colors
string[] h = new string[4];
h[0] = "#FFFFFF";
h[1] = "#000000";
h[2] = "#FFFF00";
h[3] = "#ABC19D";
// convert the hex values to colors
Color[] colors = new Color[4];
colors[0] = Snippets00001.HexStringToColor(h[0]);
colors[1] = Snippets00001.HexStringToColor(h[1]);
colors[2] = Snippets00001.HexStringToColor(h[2]);
colors[3] = Snippets00001.HexStringToColor(h[3]);
// print the results
lblOutput.Text = "";
for (int i=0; i<h.Length; i++)
{
lblOutput.Text += h[i] + " = "
+ colors[i].Name + ", Red=" + colors[i].R.ToString()
+ ", Green=" + colors[i].G.ToString()
+ ", Blue=" + colors[i].B.ToString()
+ "<br>";
}
}
If you run the previous method you'll get the following output displayed in the Label control on the aspx page.
Example: Output
#FFFFFF = ffffffff, Red=255, Green=255, Blue=255
#000000 = ff000000, Red=0, Green=0, Blue=0
#FFFF00 = ffffff00, Red=255, Green=255, Blue=0
#ABC19D = ffabc19d, Red=171, Green=193, Blue=157
namespace Cambia.CoreLib
{
using System;
using System.Drawing;
using System.Text.RegularExpressions;
/// <summary>
/// Useful C# snippets from CambiaResearch.com
/// </summary>
public class Snippets00001
{
public Snippets00001()
{
}
/// <summary>
/// Convert a hex string to a .NET Color object.
/// </summary>
/// <param name="hexColor">a hex string: "FFFFFF", "#000000"</param>
public static Color HexStringToColor(string hexColor)
{
string hc = ExtractHexDigits(hexColor);
if (hc.Length != 6)
{
// you can choose whether to throw an exception
//throw new ArgumentException("hexColor is not exactly 6 digits.");
return Color.Empty;
}
string r = hc.Substring(0, 2);
string g = hc.Substring(2, 2);
string b = hc.Substring(4, 2);
Color color = Color.Empty;
try
{
int ri
= Int32.Parse(r, System.Globalization.NumberStyles.HexNumber);
int gi
= Int32.Parse(g, System.Globalization.NumberStyles.HexNumber);
int bi
= Int32.Parse(b, System.Globalization.NumberStyles.HexNumber);
color = Color.FromArgb(ri, gi, bi);
}
catch
{
// you can choose whether to throw an exception
//throw new ArgumentException("Conversion failed.");
return Color.Empty;
}
return color;
}
/// <summary>
/// Extract only the hex digits from a string.
/// </summary>
public static string ExtractHexDigits(string input)
{
// remove any characters that are not digits (like #)
Regex isHexDigit
= new Regex("[abcdefABCDEF\\d]+", RegexOptions.Compiled);
string newnum = "";
foreach (char c in input)
{
if (isHexDigit.IsMatch(c.ToString()))
newnum += c.ToString();
}
return newnum;
}
}
}