MFMessageComposeViewController.Notifications.ObserveTextMessageAvailabilityDidChange 方法
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
重载
ObserveTextMessageAvailabilityDidChange(EventHandler<MFMessageAvailabilityChangedEventArgs>)
常量的强类型通知 TextMessageAvailabilityDidChangeNotification 。
public static Foundation.NSObject ObserveTextMessageAvailabilityDidChange(EventHandler<MessageUI.MFMessageAvailabilityChangedEventArgs> handler);static member ObserveTextMessageAvailabilityDidChange : EventHandler<MessageUI.MFMessageAvailabilityChangedEventArgs> -> Foundation.NSObject参数
发布通知时调用的方法。
返回
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
以下示例演示开发人员如何在代码中使用此方法：
//
// Lambda style
//
// listening
notification = MFMessageComposeViewController.Notifications.ObserveTextMessageAvailabilityDidChange ((sender, args) => {
/* Access strongly typed args */
Console.WriteLine ("Notification: {0}", args.Notification);
Console.WriteLine ("TextMessageAvailability", args.TextMessageAvailability);
});
// To stop listening:
notification.Dispose ();
//
//Method style
//
NSObject notification;
void Callback (object sender, MessageUI.MFMessageAvailabilityChangedEventArgs args)
{
// Access strongly typed args
Console.WriteLine ("Notification: {0}", args.Notification);
Console.WriteLine ("TextMessageAvailability", args.TextMessageAvailability);
}
void Setup ()
{
notification = MFMessageComposeViewController.Notifications.ObserveTextMessageAvailabilityDidChange (Callback);
}
void Teardown ()
{
notification.Dispose ();
}
适用于
ObserveTextMessageAvailabilityDidChange(NSObject, EventHandler<MFMessageAvailabilityChangedEventArgs>)
常量的强类型通知 TextMessageAvailabilityDidChangeNotification 。
public static Foundation.NSObject ObserveTextMessageAvailabilityDidChange(Foundation.NSObject objectToObserve, EventHandler<MessageUI.MFMessageAvailabilityChangedEventArgs> handler);static member ObserveTextMessageAvailabilityDidChange : Foundation.NSObject * EventHandler<MessageUI.MFMessageAvailabilityChangedEventArgs> -> Foundation.NSObject参数
- objectToObserve
- NSObject
要观察的对象。
发布通知时调用的方法。
返回
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 TextMessageAvailabilityDidChangeNotification 通知。
// Listen to all notifications posted for any object
var token = MFMessageComposeViewController.Notifications.ObserveTextMessageAvailabilityDidChange ((notification) => {
Console.WriteLine ("Observed TextMessageAvailabilityDidChangeNotification!");
};
// Listen to all notifications posted for a single object
var token = MFMessageComposeViewController.Notifications.ObserveTextMessageAvailabilityDidChange (objectToObserve, (notification) => {
Console.WriteLine ($"Observed TextMessageAvailabilityDidChangeNotification for {nameof (objectToObserve)}!");
};
// Stop listening for notifications
token.Dispose ();