private void OnAddTransactionItem(string obj)
        {
            var ti  = new InventoryTransactionItem();
            var tiv = new TransactionItemViewModel(ti, Workspace, _inventoryService);

            Model.TransactionItems.Add(ti);
            TransactionItems.Add(tiv);
            SelectedTransactionItem = tiv;
        }
 public TransactionItemViewModel(InventoryTransactionItem model, IWorkspace workspace, IInventoryService inventoryService)
 {
     _workspace        = workspace;
     _inventoryService = inventoryService;
     Model             = model;
 }