asynchronous operations

• Gets a value that represents the result of an asynchronous operation
  获取表示异步操作结果的值。
• Enables asynchronous operation support
  ，则启用异步操作支持。
• The asynchronous operation did not complete correctly and the
  ，则说明异步操作没有正确完成，并且
• Method to start an asynchronous operation
  方法启动异步操作。
• That receives the notification of the asynchronous operation completion
  将接收异步操作完成通知的
• Asynchronous operations that use events
  使用事件的异步操作。
• Is running an asynchronous operation
  是否正在运行异步操作。
• Using an asynccallback delegate to end an asynchronous operation
  使用asynccallback委托结束异步操作
• Gets a value that represents the argument of an asynchronous operation
  获取表示异步操作参数的值。
• Once an asynchronous operation completes , you can call
  异步操作完成后，可以再次在事件处理程序中调用