CommandBinding.CanExecute 事件

public:
 event System::Windows::Input::CanExecuteRoutedEventHandler ^ CanExecute;

public event System.Windows.Input.CanExecuteRoutedEventHandler CanExecute;

member this.CanExecute : System.Windows.Input.CanExecuteRoutedEventHandler 

Public Custom Event CanExecute As CanExecuteRoutedEventHandler 

Public Event CanExecute As CanExecuteRoutedEventHandler 

事件類型

範例

以下範例建立 a CommandBinding ，將 a ExecutedRoutedEventHandler 映射到 和 CanExecuteRoutedEventArgs handler 到 指令 Open 。

<Window.CommandBindings>
  <CommandBinding Command="ApplicationCommands.Open"
                  Executed="OpenCmdExecuted"
                  CanExecute="OpenCmdCanExecute"/>
</Window.CommandBindings>

// Creating CommandBinding and attaching an Executed and CanExecute handler
CommandBinding OpenCmdBinding = new CommandBinding(
    ApplicationCommands.Open,
    OpenCmdExecuted,
    OpenCmdCanExecute);

this.CommandBindings.Add(OpenCmdBinding);

' Creating CommandBinding and attaching an Executed and CanExecute handler
Dim OpenCmdBinding As New CommandBinding(ApplicationCommands.Open, AddressOf OpenCmdExecuted, AddressOf OpenCmdCanExecute)

Me.CommandBindings.Add(OpenCmdBinding)

以下顯示 ， CanExecuteRoutedEventHandler 該 設定 CanExecute 為 true。

void OpenCmdCanExecute(object sender, CanExecuteRoutedEventArgs e)
{
    e.CanExecute = true;
}

Private Sub OpenCmdCanExecute(ByVal sender As Object, ByVal e As CanExecuteRoutedEventArgs)
    e.CanExecute = True
End Sub

備註

當 CanExecute a RoutedCommand 上的方法被呼叫時，指令目標會觸發該 PreviewCanExecute 事件。 若事件未被處理，事件 CanExecute 將被提出。 如果指令目標有該指令的 a CommandBinding ， CanExecute 則會呼叫該 CommandBinding 指令的處理器。 如果指令目標沒有 a CommandBinding for 該指令，事件會 CanExecute 在元素樹中冒泡，搜尋與該指令相關的 CommandBinding 元素。

路由事件資訊

• 對應的隧道事件為 PreviewCanExecute。

另請參閱

• RoutedCommand
• InputBinding
• CommandManager