[Foundation.Advice("Use PdfView.Notifications.ObserveSelectionChanged helper method instead.")]
[Foundation.Field("PDFViewSelectionChangedNotification", "PDFKit")]
public static Foundation.NSString SelectionChangedNotification { get; }

[Foundation.Advice("Use PdfView.Notifications.ObserveSelectionChanged helper method instead.")]
[Foundation.Field("PDFViewSelectionChangedNotification", "Quartz")]
public static Foundation.NSString SelectionChangedNotification { get; }

member this.SelectionChangedNotification : Foundation.NSString

此常量可用于 NSNotificationCenter 注册此通知的侦听器，开发人员也可以改用强类型通知 ObserveSelectionChanged 。 这是 NSString 而不是字符串，因为这些值可以用作某些本机库中的标记，而不是纯粹用于其实际字符串内容。 回调的“notification”参数包含特定于通知类型的额外信息。

// Lambda style
NSNotificationCenter.DefaultCenter.AddObserver (
        PdfView.SelectionChangedNotification, (notification) => {Console.WriteLine ("Received the notification PdfView", notification); }
// Method style
void Callback (NSNotification notification)
    Console.WriteLine ("Received a notification PdfView", notification);
void Setup ()
    NSNotificationCenter.DefaultCenter.AddObserver (PdfView.SelectionChangedNotification, Callback);