Question

My idea was to switch between some colors, so I don’t have to use multiple pens but I can declare just one.

I’m not so sure to have understood exactly how enums work, please correct me:

type ColorType =
  | Red = Color.Red
  | Green = Color.Green
  | Blue = Color.Blue

and I wish to use it in:

let p = new Pen(ColorType.[index])
g.DrawRectangle(p, 0, 0, 10, 10)

where index is an int variable (0 to 2) I’ll use to switch my colors. The problem is that I can’t declare that enum, Color is not accepted. Possible solutions?

Answer 1

To access the colors by index, you could put them in an array:

let colors =
  [|
    Color.Red
    Color.Green
    Color.Blue
  |]

let p = new Pen(colors.[index])
g.DrawRectangle(p, 0, 0, 10, 10)