Question

I have an object of type FSharpOption, but I don’t know it’s depth. It could be any of…

FSharpOption<Int32>
FSharpOption<FSharpOption<Int32>>
FSharpOption<FSharpOption<FSharpOption<Int32>>>
FSharpOption<FSharpOption<FSharpOption<FSharpOption<Int32>>>>
etc.

Edit: Also note that it isn’t necessarily an Int32. It could be any underlying type.

How do I get at the underling value using VB or C#?

Answer 1

That may not be version independent… how about this minor variation with no dependency on FSharp.Core?

static object OptionGetUnderlyingValue(object obj)
{
    while (obj != null && obj.GetType().Name == "FSharpOption`1")
    {
        PropertyInfo pi = obj.GetType().GetProperty("Value");
        Contract.Assert(pi != null);
        obj = pi.GetValue(obj, null);
    }

    return obj;
}