UIWindow.Notifications.ObserveDidBecomeKey Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Overloads
| ObserveDidBecomeKey(EventHandler<NSNotificationEventArgs>) |
Strongly typed notification for the DidBecomeKeyNotification constant. |
| ObserveDidBecomeKey(NSObject, EventHandler<NSNotificationEventArgs>) |
Strongly typed notification for the DidBecomeKeyNotification constant. |
ObserveDidBecomeKey(EventHandler<NSNotificationEventArgs>)
Strongly typed notification for the DidBecomeKeyNotification constant.
public static Foundation.NSObject ObserveDidBecomeKey (EventHandler<Foundation.NSNotificationEventArgs> handler);static member ObserveDidBecomeKey : EventHandler<Foundation.NSNotificationEventArgs> -> Foundation.NSObjectParameters
- handler
- EventHandler<NSNotificationEventArgs>
Method to invoke when the notification is posted.
Returns
Token object that can be used to stop receiving notifications by either disposing it or passing it to RemoveObservers(IEnumerable<NSObject>)
Remarks
The following example shows how you can use this method in your code
//
// Lambda style
//
// listening
notification = UIWindow.Notifications.ObserveDidBecomeKey ((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 = UIWindow.Notifications.ObserveDidBecomeKey (Callback);
}
void Teardown ()
{
notification.Dispose ();
}
Applies to
ObserveDidBecomeKey(NSObject, EventHandler<NSNotificationEventArgs>)
Strongly typed notification for the DidBecomeKeyNotification constant.
public static Foundation.NSObject ObserveDidBecomeKey (Foundation.NSObject objectToObserve, EventHandler<Foundation.NSNotificationEventArgs> handler);static member ObserveDidBecomeKey : Foundation.NSObject * EventHandler<Foundation.NSNotificationEventArgs> -> Foundation.NSObjectParameters
- objectToObserve
- NSObject
The object to observe.
- handler
- EventHandler<NSNotificationEventArgs>
Method to invoke when the notification is posted.
Returns
Token object that can be used to stop receiving notifications by either disposing it or passing it to RemoveObservers(IEnumerable<NSObject>)
Remarks
This method can be used to subscribe for DidBecomeKeyNotification notifications.
// Listen to all notifications posted for any object
var token = UIWindow.Notifications.ObserveDidBecomeKey ((notification) => {
Console.WriteLine ("Observed DidBecomeKeyNotification!");
};
// Listen to all notifications posted for a single object
var token = UIWindow.Notifications.ObserveDidBecomeKey (objectToObserve, (notification) => {
Console.WriteLine ($"Observed DidBecomeKeyNotification for {nameof (objectToObserve)}!");
};
// Stop listening for notifications
token.Dispose ();