##works
        private int _id;
        private String _name;
        private SongsTags _songstags;


        public virtual int id
        {
            get { return this._id; }
            set { this._id = value; }
        }

        public virtual String name
        {
            get { return this._name; }
            set { this._name = value; }
        }

        public virtual SongsTags st
        {
            get { return this._songstags; }
            set { this._songstags = value; }
        }

## does not work

        public virtual int id { get; set; }

        public virtual String name { get; set; }

        public virtual SongsTags st { get; set; }