UIKeyboard.Notifications.ObserveWillShow Method

Definition

Namespace:

UIKit

Assembly:

Xamarin.iOS.dll

Overloads

ObserveWillShow(EventHandler<UIKeyboardEventArgs>)	Strongly typed notification for the WillShowNotification constant.
ObserveWillShow(NSObject, EventHandler<UIKeyboardEventArgs>)	Strongly typed notification for the WillShowNotification constant.

ObserveWillShow(EventHandler<UIKeyboardEventArgs>)

Strongly typed notification for the WillShowNotification constant.

public static Foundation.NSObject ObserveWillShow (EventHandler<UIKit.UIKeyboardEventArgs> handler);

static member ObserveWillShow : EventHandler<UIKit.UIKeyboardEventArgs> -> Foundation.NSObject

Parameters

handler

EventHandler<UIKeyboardEventArgs>

Method to invoke when the notification is posted.

Returns

NSObject

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 = UIKeyboard.Notifications.ObserveWillShow ((sender, args) => {
    /* Access strongly typed args */
    Console.WriteLine ("Notification: {0}", args.Notification);

    Console.WriteLine ("FrameBegin", args.FrameBegin);
    Console.WriteLine ("FrameEnd", args.FrameEnd);
    Console.WriteLine ("AnimationDuration", args.AnimationDuration);
    Console.WriteLine ("AnimationCurve", args.AnimationCurve);
});

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

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

    Console.WriteLine ("FrameBegin", args.FrameBegin);
    Console.WriteLine ("FrameEnd", args.FrameEnd);
    Console.WriteLine ("AnimationDuration", args.AnimationDuration);
    Console.WriteLine ("AnimationCurve", args.AnimationCurve);
}

void Setup ()
{
    notification = UIKeyboard.Notifications.ObserveWillShow (Callback);
}

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

ObserveWillShow(NSObject, EventHandler<UIKeyboardEventArgs>)

Strongly typed notification for the WillShowNotification constant.

public static Foundation.NSObject ObserveWillShow (Foundation.NSObject objectToObserve, EventHandler<UIKit.UIKeyboardEventArgs> handler);

static member ObserveWillShow : Foundation.NSObject * EventHandler<UIKit.UIKeyboardEventArgs> -> Foundation.NSObject

Parameters

objectToObserve

NSObject

The object to observe.

handler

EventHandler<UIKeyboardEventArgs>

Method to invoke when the notification is posted.

Returns

NSObject

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 WillShowNotification notifications.

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

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

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