private void OnAddItem()
        {
            IItem item = this.itemFactory.CreateItem().Result;

            Dialogs.DialogItem.DialogItemViewModel vm = new Dialogs.DialogItem.DialogItemViewModel(item);
            DialogFactory dialogFactory = new DialogFactory();
            DialogResult  dialogResult  = dialogFactory.ShowDialog("Item", vm);
        }
        private void OnEditItem(object value)
        {
            if (value == null)
            {
                return;
            }

            Models.Models.Item item = value as Models.Models.Item;
            if (item == null)
            {
                return;
            }

            Dialogs.DialogItem.DialogItemViewModel vm = new Dialogs.DialogItem.DialogItemViewModel(item);
            DialogFactory dialogFactory = new DialogFactory();
            DialogResult  dialogResult  = dialogFactory.ShowDialog("Item", vm);
            //if (dialogResult == DialogResult.OK)
            //{
            //    OnPropertyChanged("Items");
            //}
        }