PKPassLibrary.Notifications.ObserveDidChange 方法

定義

命名空間:

PassKit

組件:

Xamarin.iOS.dll

多載

ObserveDidChange(EventHandler<NSNotificationEventArgs>)	常數的 DidChangeNotification 強型別通知。
ObserveDidChange(NSObject, EventHandler<NSNotificationEventArgs>)	常數的 DidChangeNotification 強型別通知。

ObserveDidChange(EventHandler<NSNotificationEventArgs>)

常數的 DidChangeNotification 強型別通知。

public static Foundation.NSObject ObserveDidChange (EventHandler<Foundation.NSNotificationEventArgs> handler);

static member ObserveDidChange : EventHandler<Foundation.NSNotificationEventArgs> -> Foundation.NSObject

參數

handler

EventHandler<NSNotificationEventArgs>

張貼通知時叫用的方法。

傳回

NSObject

權杖物件，可用來停止接收通知，方法是處置通知或傳遞至 RemoveObservers(IEnumerable<NSObject>)

備註

下列範例示範如何在程式碼中使用此方法

//
// Lambda style
//

// listening
notification = PKPassLibrary.Notifications.ObserveDidChange ((sender, args) => {
    /* Access strongly typed args */
    Console.WriteLine ("Notification: {0}", args.Notification);
});

// To stop listening:
notification.Dispose ();

//
//Method style
//
NSObject notification;
void Callback (object sender, Foundation.NSNotificationEventArgs args)
{
    // Access strongly typed args
    Console.WriteLine ("Notification: {0}", args.Notification);
}

void Setup ()
{
    notification = PKPassLibrary.Notifications.ObserveDidChange (Callback);
}

void Teardown ()
{
    notification.Dispose ();
}

ObserveDidChange(NSObject, EventHandler<NSNotificationEventArgs>)

常數的 DidChangeNotification 強型別通知。

public static Foundation.NSObject ObserveDidChange (Foundation.NSObject objectToObserve, EventHandler<Foundation.NSNotificationEventArgs> handler);

static member ObserveDidChange : Foundation.NSObject * EventHandler<Foundation.NSNotificationEventArgs> -> Foundation.NSObject

參數

objectToObserve

NSObject

要觀察的物件。

handler

EventHandler<NSNotificationEventArgs>

張貼通知時叫用的方法。

傳回

NSObject

權杖物件，可用來停止接收通知，方法是處置通知或傳遞至 RemoveObservers(IEnumerable<NSObject>)

備註

這個方法可用來訂閱 DidChangeNotification 通知。

// Listen to all notifications posted for any object
var token = PKPassLibrary.Notifications.ObserveDidChange ((notification) => {
	Console.WriteLine ("Observed DidChangeNotification!");
};

// Listen to all notifications posted for a single object
var token = PKPassLibrary.Notifications.ObserveDidChange (objectToObserve, (notification) => {
	Console.WriteLine ($"Observed DidChangeNotification for {nameof (objectToObserve)}!");
};

// Stop listening for notifications
token.Dispose ();