How to get the name of color while having its RGB value in C#?

Question

I am creating an application to find the most used color of an image, i am up to getting the RGB value of the color, but how to get the color name, help plz.

Answer 1

As noted in comments, the KnownColor enumeration can be used to make this simpler:

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Reflection;

class Test
{
    static void Main()
    {
        Color color = Color.FromArgb(255, 0, 0);
        Console.WriteLine(color.Name); // ffff0000

        var colorLookup = Enum.GetValues(typeof(KnownColor))
               .Cast<KnownColor>()
               .Select(Color.FromKnownColor)
               .ToLookup(c => c.ToArgb());

        // There are some colours with multiple entries...
        foreach (var namedColor in colorLookup[color.ToArgb()])
        {
            Console.WriteLine(namedColor.Name);
        }
    }
}

---

Original answer

Color.FromArgb will give you a Color, but it will never have a name. You need to use reflection to get the named colours, as far as I'm aware.

Here's another version of Cole Campbell's solution which I was working up at the same time...

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Reflection;

class Test
{
    static void Main()
    {
        Color color = Color.FromArgb(255, 0, 0);
        Console.WriteLine(color.Name); // ffff0000

        var colorLookup = typeof(Color)
               .GetProperties(BindingFlags.Public | BindingFlags.Static)
               .Select(f => (Color) f.GetValue(null, null))
               .Where(c => c.IsNamedColor)
               .ToLookup(c => c.ToArgb());

        // There are some colours with multiple entries...
        foreach (var namedColor in colorLookup[color.ToArgb()])
        {
            Console.WriteLine(namedColor.Name);
        }
    }
}

Answer 2

This method uses reflection to examine the predefined colors on the Color class and compare them against the color passed in as an argument. This can be optimized further, but it should give you an idea of the general technique.

private static String GetColorName(Color color)
{
    var predefined = typeof(Color).GetProperties(BindingFlags.Public | BindingFlags.Static);
    var match = (from p in predefined where ((Color)p.GetValue(null, null)).ToArgb() == color.ToArgb() select (Color)p.GetValue(null, null));
    if (match.Any())
       return match.First().Name;
    return String.Empty;
}

Answer 3

You should be able to use the Color class from System.Drawing namespace, it has a static method FromARGB that returns a Color object. It has several overloads, one allowing you to enter the RGB values like so:

var color = Color.FromArgb(100, 5,5,5).Name;

Answer 4

For something quick and simple, try this (in WPF):

public string GetNameOfColor(Color color) {
    var colorProperty = typeof(Colors).GetProperties().FirstOrDefault(p =>
        (Color)(p.GetValue(p, null)) == color);
    return (colorProperty != null) ? colorProperty.Name : color.ToString();
}

In Visual Studio 2010, the p.GetValue(p, null) is required. In Visual Studio 2013+ you can just use p.GetValue(p).

The advantage of this technique, besides its brevity, is that it doesn't require references to System.Drawing or System.Reflection but allows the user to remain inside the System.Windows namespace, which is WPF. It does require a reference to System.Windows.Media which you should probably already have if you are working with Colors in WPF. If you are like me, you try not to add System.Drawing to your WPF applications without a good need. As to why stay inside the WPF namespace, its a matter of preference. See for instance discussions at WPF v/s System.Drawing.