public KisiViewModel()
{
Title = "Veriler";
KisiObsvList = new ObservableCollection <Kisi>();
LoadItemsCommand = new Command(async() => await ExecuteLoadItemsCommand());
MessagingCenter.Subscribe <YeniKisiPage, Kisi>(this, "AddKisi", async(obj, item) =>
{
var _item = item as Kisi;
KisiObsvList.Add(_item);
await DataStore.AddKisiAsync(_item);
});
}