Convert System.Drawing.Color to RGB and Hex Value

Question

Using C# I was trying to develop the following two. The way I am doing it may have some problem and need your kind advice. In addition, I dont know whether there is any existing method to do the same.

private static String HexConverter(System.Drawing.Color c)
{
    String rtn = String.Empty;
    try
    {
        rtn = "#" + c.R.ToString("X2") + c.G.ToString("X2") + c.B.ToString("X2");
    }
    catch (Exception ex)
    {
        //doing nothing
    }

    return rtn;
}

private static String RGBConverter(System.Drawing.Color c)
{
    String rtn = String.Empty;
    try
    {
        rtn = "RGB(" + c.R.ToString() + "," + c.G.ToString() + "," + c.B.ToString() + ")";
    }
    catch (Exception ex)
    {
        //doing nothing
    }

    return rtn;
}

Thanks.

Fissiparous

@Rod #20750562 – Immobility

Answer 1

I'm failing to see the problem here. The code looks good to me.

The only thing I can think of is that the try/catch blocks are redundant -- Color is a struct and R, G, and B are bytes, so c can't be null and c.R.ToString(), c.G.ToString(), and c.B.ToString() can't actually fail (the only way I can see them failing is with a NullReferenceException, and none of them can actually be null).

You could clean the whole thing up using the following:

private static String ToHex(System.Drawing.Color c)
    => $"#{c.R:X2}{c.G:X2}{c.B:X2}"
    
private static String ToRGB(System.Drawing.Color c)
    => $"RGB({c.R},{c.G},{c.B})"

Iodism

I'd go so far as to say that empty try-catch blocks should (almost) universally be eradicated. They have great potential to lead to buggy code, if not now then down the road when this code is modified. Still, +1 for the cleaned up code, and to the OP +1 for a well-framed question. – Ilario

Took me a while to find the VB equivelant: String.Format("#{0:X2}{1:X2}{2:X2}", c.R, c.G, c.B) – Falkirk

I post an adaptation of your code to C#6 as an alternative answer. You can see it here. – Leelah

This will produce the wrong color if the color has an alpha channel (transparency). You will get full opaqueness. – Surveillance

@Surveillance Absolutely true, and thank you for pointing it out. My example skipped the alpha channel only because I was keying off of the original question, which also didn't include it. :) – Iodism

@Surveillance this answer supports alpha channel – Leelah

Answer 2

You could keep it simple and use the native color translator:

Color red = ColorTranslator.FromHtml("#FF0000");
string redHex = ColorTranslator.ToHtml(red);

Then break the three color pairs into integer form:

int value = int.Parse(hexValue, System.Globalization.NumberStyles.HexNumber);

Inopportune

But if I do this way, Color red = System.Drawing.Color.Red; string redHex = ColorTranslator.ToHtml(red); it does not provide the Hex Value. – Fissiparous

Certainly should do, I tested that code specifically and got #"FF0000". What are you getting? You might also like to refer to the MSDN reference: msdn.microsoft.com/en-us/library/… – Inopportune

Try with Color red = System.Drawing.Color.Red; --> it does not provide #FF0000. – Fissiparous

So using exactly the first code block I provided, what is the value of redHex? I think something on your side is missing. – Inopportune

The code you have provided works but when I change the first line of your code to : Color red = System.Drawing.Color.Red; --> Then it does not give the hex code. It gives "Red" as an output. – Fissiparous

@Hoque - Confirmed. ColorTranslator gives a "friendly" name to the color. How annoying! – Prosciutto

+1 bc this caused me to look at the .NET implementation of ColorTranslator which is the accepted answer + KnownColor logic. i didn't want that logic, so i went with the accepted answer (but made extension methods) – Phyletic

This may not be suitable for some cases, because a quick test within a WinForm lead to the following result: System.Drawing.ColorTranslator.ToHtml(Me.BackColor) = "buttonface" instead of the (desired) hex value. – Ted

One other thing to be aware is that any Alpha values of your color are lost! – Auroraauroral

Answer 3

If you can use C#6 or higher, you can benefit from Interpolated Strings and rewrite @Ari Roth's solution like this:

C# 6:

public static class ColorConverterExtensions
{
    public static string ToHexString(this Color c) => $"#{c.R:X2}{c.G:X2}{c.B:X2}";

    public static string ToRgbString(this Color c) => $"RGB({c.R}, {c.G}, {c.B})";
}

Also:

• I add the keyword this to use them as extensions methods.
• We can use the type keyword string instead of the class name.
• We can use lambda syntax.
• I rename them to be more explicit for my taste.

Edit: If you want to support the alpha channel:

public static class ColorConverterExtensions
{
    // #RRGGBB
    public static string ToHexString(this Color c) => $"#{c.R:X2}{c.G:X2}{c.B:X2}";

    // RGB(R, G, B)
    public static string ToRgbString(this Color c) => $"RGB({c.R}, {c.G}, {c.B})";

    // #RRGGBBAA
    public static string ToHexaString(this Color c) => $"#{c.R:X2}{c.G:X2}{c.B:X2}{c.A:X2}";

    private static double ToProportion(byte b) => b / (double)Byte.MaxValue;

    // RGBA(R, G, B, A)
    public static string ToRgbaString(this Color c) => $"RGBA({c.R}, {c.G}, {c.B}, {ToProportion(c.A):N2})";
}

Fun fact: I have to search about the proportion name, because we want for a value in the interval [0, 1] not a percent which is in the interval [0, 100]

• https://english.stackexchange.com/a/286524/70403
• https://english.stackexchange.com/questions/218655/a-number-between-0-and-1-like-a-percentage-but-expressed-as-a-decimal
• https://math.stackexchange.com/questions/890617/name-for-percentage-as-a-decimal-between-0-and-1-inclusive
• https://math.stackexchange.com/questions/1626783/is-there-a-name-for-numbers-between-0-and-1

Leelah

Answer 4

e.g.

 ColorTranslator.ToHtml(Color.FromArgb(Color.Tomato.ToArgb()))

This can avoid the KnownColor trick.

Garv

Answer 5

For hexadecimal code try this

1. Get ARGB (Alpha, Red, Green, Blue) representation for the color
2. Filter out Alpha channel: & 0x00FFFFFF
3. Format out the value (as hexadecimal "X6" for hex)

For RGB one

1. Just format out Red, Green, Blue values

Implementation

private static string HexConverter(Color c) {
  return String.Format("#{0:X6}", c.ToArgb() & 0x00FFFFFF);
}

public static string RgbConverter(Color c) {
  return String.Format("RGB({0},{1},{2})", c.R, c.G, c.B);
}

Lettering

Answer 6

I found an extension method that works quite well

public static string ToHex(this Color color)
{
    return String.Format("#{0}{1}{2}{3}"
        , color.A.ToString("X").Length == 1 ? String.Format("0{0}", color.A.ToString("X")) : color.A.ToString("X")
        , color.R.ToString("X").Length == 1 ? String.Format("0{0}", color.R.ToString("X")) : color.R.ToString("X")
        , color.G.ToString("X").Length == 1 ? String.Format("0{0}", color.G.ToString("X")) : color.G.ToString("X")
        , color.B.ToString("X").Length == 1 ? String.Format("0{0}", color.B.ToString("X")) : color.B.ToString("X"));
}

Ref: https://social.msdn.microsoft.com/Forums/en-US/4c77ba6c-6659-4a46-920a-7261dd4a15d0/how-to-convert-rgba-value-into-its-equivalent-hex-code?forum=winappswithcsharp

Sovereignty

I belive it should be Hex2, not Hex, otherwise the color maybe wrong interpolated. – Warrantee

@MohammedNoureldin Where would Hex2 go in the code, I have seen colours being slightly different sometimes? – Sovereignty

I meant X2 instead of X, otherwise you might get 1 instead of 01 then it will be a problem. – Warrantee

@MohammedNoureldin Yeah, with X2 then you don't need all the color.B.ToString("X").Length == 1 ? ternaries. – Vanettavang

To make this work with web browsers I had to switch the formatting so that the alpha parameter would be added last. – Methylnaphthalene