private ObservableCollection<EquipmentItem> _optionalCollection;

        public ObservableCollection<EquipmentItem> OptionalCollection

        {

            get

            {

                if (this._optionalCollection == null)

                {

                    this._optionalCollection = new ObservableCollection<EquipmentItem>();

                }

                return this._optionalCollection;

            }

            set

            {

                if (value != this._optionalCollection)

                {

                    if (this._optionalCollection != null)

                    {

                        this._optionalCollection.Clear();

                    }

                    this._optionalCollection = value;

                    this.RaisePropertyChangedEvent("OptionalCollection");

                }

            }

        }