问如何在特定日期后停止触发计划的本地通知？

EN

var content = new UNMutableNotificationContent();
    content.Title = "Title";
    content.Subtitle = "Subtitle";
    content.Body = "Body";
    content.Badge = 1;
    content.CategoryIdentifier = categoryID;
    content.Sound = UNNotificationSound.Default;

    var d = new NSDateComponents {
        Hour = 14
    };
    //Repeat is true, so it will keep triggering when ever the hour reads 14
    var newTrigger = UNCalendarNotificationTrigger.CreateTrigger(d, true);
    var requestID = "notificationRequest";
    var request = UNNotificationRequest.FromIdentifier(requestID, content, newTrigger);

    //Here I set the Delegate to handle the user tapping on notification
    UNUserNotificationCenter.Current.Delegate = new CustomUNUserNotificationCenterDelegate();

    UNUserNotificationCenter.Current.AddNotificationRequest(request, (err) => {
        if (err != null) {
            // Report error
            System.Console.WriteLine("Error: {0}", err);
        } else {
            // Report Success
            System.Console.WriteLine("Notification Scheduled: {0}", request);
        }
    });

public override void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)  {
    DateTime StartDate = new DateTime(2018, 6, 1, 0, 0, 0);
    DateTime EndDate = new DateTime(2018, 6, 28, 0, 0, 0);
    if ((DateTime.Now > StartDate) && (DateTime.Now < EndDate)) {
        UIAlertView alertView = new UIAlertView();
        alertView.Message = "within the date range";
        alertView.AddButton("OK");
        alertView.Show();
        completionHandler(UNNotificationPresentationOptions.Alert | UNNotificationPresentationOptions.Sound | UNNotificationPresentationOptions.Badge);
    } else {
        var requests = new string[] { "notificationRequest" };
        UNUserNotificationCenter.Current.RemovePendingNotificationRequests(requests);
    }
}

        //This is just test data
        var d = new NSDateComponents();
        NSCalendar currCal = new NSCalendar(NSCalendarType.Gregorian);
        var d1 = new NSDateComponents();
        d1.Day = 29;
        d1.Month = 5;
        d1.Year = 2018;
        d1.Hour = 12;
        d1.Minute = 58;
        d1.Second = 00;
        var d2 = new NSDateComponents();
        d2.Day = 29;
        d2.Month = 5;
        d2.Year = 2018;
        d2.Hour = 13;
        d2.Minute = 02;
        d2.Second = 00;
        currCal.ComponentsFromDateToDate(NSCalendarUnit.Second, d1, d2, NSCalendarOptions.None);
        d.Second = 10;
        d.Calendar = currCal;