You are developing a Windows Presentation Foundation (WPF) application. An event triggers a workflow such that a parent control executes the event handlers before the child controls. You need to ensure that if a parent controls event handler encounters an error, the subsequent handlers are not called. What should you do?()
A. Use handlers for a tunneling routed event and mark the event as handled in the case of a problem.
B. Use handlers for a tunneling routed event and make the event as handled in the finally portion of a try-catch-finally code block.
C. Use handlers for a bubbling routed event and mark the event as handled in the case of a problem.
D. Use handlers for a bubbling routed event and set the Handled property of the RoutedEventArgs object to true in the catch portion of a try-catch-finally code block.
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当采用了新技术、使用了新设备,民航空管运行单位应当进行年度安全培训。
A. 正确
B. 错误
民航空管从业人员经安全教育和培训后考核不合格的,经单位领导批准后可以上岗作业。
A. 正确
B. 错误