public AddItemToStoreViewModel()
 {
     Items      = new BindableCollection <Item>(ItemsProcessor.GetItems <Item>());
     Stores     = new BindableCollection <Store>(StoreProcessor.GetStores <Store>());
     Vendors    = new BindableCollection <Vendor>(VendorsProcessor.GetVendors <Vendor>());
     StoreItems = new BindableCollection <Item>();
 }