public void LoadAllListingTypes()
        {
            Data.Repository respository = new Data.Repository();

            try
            {
                ObservableCollection<ListingType> listingTypes = respository.GetAllListingTypes();
            }
            catch (Exception ex)
            {
                throw ex;
            }

            try
            {
                this.ListingTypes = listingTypes.ToViewModels();
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }