Question

Here is my serializable abstract class

namespace NEN_FS {
    [Serializable()]
    abstract public class NFS : IEquatable<NFS> {
        abstract public string Path { get; set; }
        public NFS() {
            Path = "";
            }
        public NFS(string path) {
            Path = path;
            }
        public override bool Equals(object obj) {
            NFS other = obj as NFS;
            return (other != null) && ((IEquatable<NFS>)this).Equals(other);
            }
        bool IEquatable<NFS>.Equals(NFS other) {
            return Path.Equals(other.Path);
            }
        public override int GetHashCode() {
            return Path != null ? Path.GetHashCode() : base.GetHashCode();
            }
        }
    }

What I have in F#: let file = files.[0]. and there is no Path field.

Why is that? How can I access Path property?

Answer 1

Huh? Strange.. maybe some bug in meta-data reading or intellisense. Try writing file.[0].Path and compiling. Sometimes the Intellisense skips something but the compiler sees whole structure right and compiles without complaints.

If not working – then maybe F# doesn’t like abstract for some reasons unknown to me (i.e. some overall nonsense like im-possibility of instantiating an ‘example object’).. I’m not fluent in F# yet, but thinking about .Net itself, have you tried to define and use an interface instead of abstract base? I mean:

namespace NEN_FS {
    public interface class INFS : IEquatable<NFS>
    {
        string Path { get; set; }
    }

    [Serializable()]
    abstract public class NFS : INFS {
        abstract public string Path { get; set; }
        public NFS() {
            Path = "";
            }
        public NFS(string path) {
            Path = path;
            }
        public override bool Equals(object obj) {
            NFS other = obj as NFS;
            return (other != null) && ((IEquatable<NFS>)this).Equals(other);
            }
        bool IEquatable<NFS>.Equals(NFS other) {
            return Path.Equals(other.Path);
            }
        public override int GetHashCode() {
            return Path != null ? Path.GetHashCode() : base.GetHashCode();
            }
        }

And then expose IEnumerable<INFS> Files instead of IEnumerable<NFS> Files. That way it just have to work, because interfaces are the core of access to many things..