Please explain this SerializationException to me.

Question

The simple class below inherits from HashSet and thus has to implement the ISerialization members (in a non standard way). I get the following Exception when I try to serialize then deserialize an instance of Group:

Test method UtilitiesTests.GroupTest.SerializeTest threw exception: System.Reflection.TargetInvocationException: Het doel van een aanroep heeft een uitzondering veroorzaakt. ---> System.Runtime.Serialization.SerializationException: Lid nameprop is niet gevonden..

Unfortunately this is in dutch. It means that the member "nameprop" could not be found! What is wrong??

using System;
using System.Collections.Generic;
using System.Runtime.Serialization;

namespace Grouping
{
    [Serializable]
    public class Group<T> : HashSet<T>
    {
        public Group(string name)
        {
            Name = name;
        }

        protected Group(){}

        protected Group(SerializationInfo info, StreamingContext context):base(info,context)
        {
            Name = info.GetString("nameprop");
        }

        protected new void GetObjectData(SerializationInfo info,StreamingContext context)
        {
            base.GetObjectData(info,context);
            info.AddValue("nameprop", Name);
        }

        public string Name { get; private set; }
    }
}

Answer 1

Your GetObjectData method is never called during serialization, because you don't override the parent method - you shadow it. You should use override rather than new there.