F# generic type constraints and duck typing

Question

I\'m trying to implement duck typing in F# and I spotted that you can have a member constraint in F# generics as follows:

type ListEntryViewModel<\'T wh         


        

Answer 1

To make your original code work:

type ListEntryViewModel< ^T when ^T : (member Name : string)>(model:^T) = 
    inherit ViewModelBase()

    member inline this.Name with get() = (^T : (member Name : string) model)

So you have to mark the member as "inline" and repeat the constraint in the member function.

I agree with Tomas that an Interface-based approach is usually preferred in F#.