What is the simplest way to access data of an F# discriminated union type in C#?

Question

I\'m trying to understand how well C# and F# can play together. I\'ve taken some code from the F# for Fun & Profit blog which performs basic validation returning a discr

Answer 1

How about this? It's inspired by @Mauricio Scheffer's comment above and the CSharpCompat code in FSharpx.

C#:

MyUnion u = CallIntoFSharpCode();
string s = u.Match(
  ifFoo: () => "Foo!",
  ifBar: (b) => $"Bar {b}!");

F#:

  type MyUnion =
    | Foo
    | Bar of int
  with
    member x.Match (ifFoo: System.Func<_>, ifBar: System.Func<_,_>) =
      match x with
      | Foo -> ifFoo.Invoke()
      | Bar b -> ifBar.Invoke(b)

What I like best about this is that it removes the possibility of a runtime error. You no longer have a bogus default case to code, and when the F# type changes (e.g. adding a case) the C# code will fail to compile.