How do I create a random hex string that represents a color?

Question

I'm generating some charts that need a hex string for the colors.

Example:

<dataseries name="ford" color="FF00FF" /> 

I'm creating these dynamically, so I would like to generate the hex code for each dataseries randomly.

What is the best way to do this?

Answer 1

Easiest way is to use String.Format and use the hexadecimal format for the argument.

var random = new Random(); var color = String.Format("#{0:X6}", random.Next(0x1000000)); // = "#A197B9" 

Answer 2

Samuel's answer is the best way to do this, just make sure that if you're generating the colors inside a loop that you don't instantiate a new Random object each time because new Random() seeds the generator using the system clock. Your loop is going to run faster than the clock can tick, so you'll end up generating several of the same colors over and over because random is being seeded with the same value.

It should look something like this:

int numColors = 10; var colors = new List<string>(); var random = new Random(); // Make sure this is out of the loop! for (int i = 0; i < numColors; i++)  {     colors.Add(String.Format("#{0:X6}", random.Next(0x1000000))); } 

instead of:

int numColors = 10; var colors = new List<string>(); for (int i = 0; i < numColors; i++)  {     var random = new Random(); // Don't put this here!     colors.Add(String.Format("#{0:X6}", random.Next(0x1000000))); }