The .NET framework has a number of predefined colours in the System.Drawing.Color class. You ‘d think this would be easy to iterate over – after all, there’s quite a lot of them. I can see that that would be useful for, say, drawing palettes.

Well it ain’t easy. They’re not an enumeration, so you can’t iterate over them. Instead, to get a list of the colours, you’ve got to do something like:

List<Color> colorList = new List<Color>();

Array colorsArray = Enum.GetValues(typeof(KnownColor));
KnownColor[] allKnownColors = new KnownColor[colorsArray.Length];
Array.Copy(colorsArray, allKnownColors, colorsArray.Length);

foreach (KnownColor c in allKnownColors) {
Color col = Color.FromKnownColor(c);
if(( col.IsSystemColor == false) && (col.A > 0)) {
colorList.Add(col);
}
}
That’s a lot of work for something obvious like iterating over colours!