private async Task DeleteEvent()
        {
            var message = await networkAPI.DeletePromotion(Promotion.PromotionId);

            await MessageUtils.ShowDialog("Promotie verwijderen", message.Item1);

            if (message.Item2)
            {
                mainPageViewModel.BackButtonPressed();
                mainPageViewModel.BackButtonPressed();
                mainPageViewModel.NavigationHistoryItems.RemoveAll(v => v.GetType() == typeof(PromotionDetailViewModel) || v.GetType() == typeof(PromotionsViewModel));
                mainPageViewModel.NavigateTo(new PromotionsViewModel(mainPageViewModel));
            }
        }