CommandBinding.CanExecute Event
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Occurs when the command associated with this CommandBinding initiates a check to determine whether the command can be executed on the command target.
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 Event Type
Examples
The following example creates a CommandBinding that maps an ExecutedRoutedEventHandler and a CanExecuteRoutedEventArgs handler to the Open command.
<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)
The following shows the CanExecuteRoutedEventHandler which sets CanExecute to 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
Remarks
When the CanExecute method on a RoutedCommand is called, the PreviewCanExecute event is raised on the command target. If the event is not handled, the CanExecute event is raised. If the command target has a CommandBinding for the command, the CanExecute handler for that CommandBinding is called. If the command target does not have a CommandBinding for the command, the CanExecute event bubbles up the element tree searching for an element that has a CommandBinding associated with the command.
Routed Event Information
| Item | Value |
|---|---|
| Identifier field | CanExecuteEvent |
| Routing strategy | Bubbling |
| Delegate | CanExecuteRoutedEventHandler |
- The corresponding tunneling event is PreviewCanExecute.
