public async void DataLoading() { await Task.Run(() => Load_Warehouses()); }

private void Load_Warehouses()
        {
            var WMod = new WarehouseModel();
            WareHouseCollection = WMod.LoadWarehouses();
            RaisePropertyChanged(nameof(WareHouseCollection));
        }

public class MyViewModel
{
   public MyViewModel(IWareHouseRepository warehouseRepository) // Mit Dependecy vermeidet man, dass man die SQL Verbindung manuell erstellt und verwalten muss
   {
      _warehouseRepository = warehouseRepository;
   }

   public ObservableCollection<WareHouseModel> WareHouseCollection {get;}  = new();

   public async Task LoadWareHouses()
   { 
      WareHouseCollection.ClearItems();
      List<WareHouseEntity> wareHouses = await _warehouseRepository.GetAllAsync();
      foreach(var wh in wareHouses )
      {
         WareHouseCollection.Add(new WareHouseModel(wh.Id, wh.Name));
      }
   }

   public ICommand LoadWareHousesCommand
   {
       get { return new DelegateCommand(LoadWareHouses); } // bin mir nicht mehr sicher, aber glaub DelegateCommand war hier das richtige
    }
}