public ItemsViewModel()
{
Title = "Browse";
Items = new ObservableRangeCollection <Item>();
LoadItemsCommand = new Command(async() => await ExecuteLoadItemsCommand());
MessagingCenter.Subscribe <NewItemPage, Item>(this, "AddItem", async(obj, item) =>
{
var _item = item as Item;
Items.Add(_item);
await ItemStore.AddAsync(_item);
});
}