NSPersistentStoreCoordinator.Notifications.ObserveStoresWillChange Method

Definition

Namespace:

CoreData

Assembly:

Xamarin.iOS.dll

Overloads

ObserveStoresWillChange(EventHandler<NSPersistentStoreCoordinatorStoreChangeEventArgs>)	Strongly typed notification for the StoresWillChangeNotification constant.
ObserveStoresWillChange(NSObject, EventHandler<NSPersistentStoreCoordinatorStoreChangeEventArgs>)	Strongly typed notification for the StoresWillChangeNotification constant.

ObserveStoresWillChange(EventHandler<NSPersistentStoreCoordinatorStoreChangeEventArgs>)

Strongly typed notification for the StoresWillChangeNotification constant.

public static Foundation.NSObject ObserveStoresWillChange (EventHandler<CoreData.NSPersistentStoreCoordinatorStoreChangeEventArgs> handler);

static member ObserveStoresWillChange : EventHandler<CoreData.NSPersistentStoreCoordinatorStoreChangeEventArgs> -> Foundation.NSObject

Parameters

handler

EventHandler<NSPersistentStoreCoordinatorStoreChangeEventArgs>

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 developers can use this method in their code:

//
// Lambda style
//

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

    Console.WriteLine ("EventType", args.EventType);
});

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

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

    Console.WriteLine ("EventType", args.EventType);
}

void Setup ()
{
    notification = NSPersistentStoreCoordinator.Notifications.ObserveStoresWillChange (Callback);
}

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

ObserveStoresWillChange(NSObject, EventHandler<NSPersistentStoreCoordinatorStoreChangeEventArgs>)

Strongly typed notification for the StoresWillChangeNotification constant.

public static Foundation.NSObject ObserveStoresWillChange (Foundation.NSObject objectToObserve, EventHandler<CoreData.NSPersistentStoreCoordinatorStoreChangeEventArgs> handler);

static member ObserveStoresWillChange : Foundation.NSObject * EventHandler<CoreData.NSPersistentStoreCoordinatorStoreChangeEventArgs> -> Foundation.NSObject

Parameters

objectToObserve

NSObject

The object to observe.

handler

EventHandler<NSPersistentStoreCoordinatorStoreChangeEventArgs>

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 StoresWillChangeNotification notifications.

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

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

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