UITextView.Notifications.ObserveTextDidChange 方法

定义

命名空间:

UIKit

程序集:

Xamarin.iOS.dll

重载

ObserveTextDidChange(EventHandler<NSNotificationEventArgs>)	常量的强类型通知 TextDidChangeNotification 。
ObserveTextDidChange(NSObject, EventHandler<NSNotificationEventArgs>)	常量的强类型通知 TextDidChangeNotification 。

ObserveTextDidChange(EventHandler<NSNotificationEventArgs>)

常量的强类型通知 TextDidChangeNotification 。

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

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

参数

handler

EventHandler<NSNotificationEventArgs>

发布通知时调用的方法。

返回

NSObject

令牌对象，可用于停止接收通知，方法是释放通知或将其传递给 RemoveObservers(IEnumerable<NSObject>)

注解

以下示例演示如何在代码中使用此方法

//
// Lambda style
//

// listening
notification = UITextView.Notifications.ObserveTextDidChange ((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 = UITextView.Notifications.ObserveTextDidChange (Callback);
}

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

ObserveTextDidChange(NSObject, EventHandler<NSNotificationEventArgs>)

常量的强类型通知 TextDidChangeNotification 。

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

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

参数

objectToObserve

NSObject

要观察的对象。

handler

EventHandler<NSNotificationEventArgs>

发布通知时调用的方法。

返回

NSObject

令牌对象，可用于停止接收通知，方法是释放通知或将其传递给 RemoveObservers(IEnumerable<NSObject>)

注解

此方法可用于订阅 TextDidChangeNotification 通知。

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

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

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