Serialized specialized list <>

I have a specialized BusinessObjectList class with this declaration:

public class BusinessObjectList<T> : List<BusinessObject> where T: BusinessObject {}

      

        
        
        
      

    

And I want to serialize objects of this class, for example:

info.AddValue("myList", myList);

      

        
        
        
      

    

I tried adding the ISerializable interface, but with no success.

public class BusinessObjectList<T> : List<BusinessObject>, ISerializable where T: BusinessObject {}

      

        
        
        
      

    

The list is always null when unserialized. I think List <> objects are serializable, but what about subclassing of them?

EDIT:

For future reference only, here is the entire class:

BusinessObjectList.cs (When you call save (), it automatically saves all inserts to the DB and removes from the list, and also saves all changed values ​​in business objects):

[Serializable()]
public class BusinessObjectList<T> : List<BusinessObject>,ISerializable where T: BusinessObject
{
    public delegate void BusinessObjectListDeleteHandler(T objDeleted);
    public event BusinessObjectListDeleteHandler deleteHandler;

    List<BusinessObject> objsForDelete = new List<BusinessObject>();
    public BusinessObjectList()
    {

    }

    public new void Add(BusinessObject item)
    {
        base.Add(item);
    }
    public new T this[int index]
    {
        get
        {                 
            return (T)base[index];
        }
    }

    public bool save()
    {
        foreach (T obj in objsForDelete)
        {
            if (deleteHandler != null)
                deleteHandler(obj);
            obj.delete();
        }
        objsForDelete.Clear();
        foreach (BusinessObject obj in this)
        {
            obj.save();
        }
        return true;
    }

    public new void Clear()
    {
        foreach (BusinessObject obj in this)
        {
            //obj.delete();
            objsForDelete.Add(obj);
        }
        base.Clear();
    }

    public new void Remove(BusinessObject obj)
    {
        // obj.delete();
        objsForDelete.Add(obj);
        base.Remove(obj);
    }

    public new void RemoveAt(int index)
    {
        objsForDelete.Add(this[index]);
        base.RemoveAt(index);
    }


    #region ISerializable Members

    public void GetObjectData(SerializationInfo info, StreamingContext context)
    {
        // should I do something here??
    }

    #endregion
}

      

        
        
        
      

    

And BusinessObject.cs:

[Serializable()]
public abstract class BusinessObject:ISerializable
{
    public abstract bool save();
    public abstract bool delete();
    public abstract DbTransaction startTransaction();
    public abstract void useTransaction(DbTransaction transaction);
    public abstract DbTransaction getTransaction();

    #region ISerializable Members

    public void GetObjectData(SerializationInfo info, StreamingContext context)
    {            
        // nothing to serialize here            
    }

    #endregion
}