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 

事件类型

示例

以下示例创建一个 ， CommandBinding 用于将 ExecutedRoutedEventHandler 和 CanExecuteRoutedEventArgs 处理程序映射到 命令 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)

下面显示了将 CanExecuteRoutedEventHandler 设置为 CanExecutetrue的 。

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

注解

CanExecute调用 上的 RoutedCommand 方法时，将在PreviewCanExecute命令目标上引发 事件。 如果未处理事件，则会引发 该 CanExecute 事件。 如果命令目标具有 CommandBinding 命令的 ，则 CanExecute 调用 的 CommandBinding 处理程序。 如果命令目标没有 CommandBinding 命令的 ，则事件将 CanExecute 向上弹出元素树，搜索具有 CommandBinding 与命令关联的 的 元素。

路由事件信息

• 相应的隧道事件为 PreviewCanExecute。

适用于

另请参阅

• RoutedCommand
• InputBinding
• CommandManager