CommandManager.AddExecutedHandler Method

Definition

Namespace:

System.Windows.Input

Assembly:

PresentationCore.dll

Attaches the specified ExecutedRoutedEventHandler to the specified element.

public:
 static void AddExecutedHandler(System::Windows::UIElement ^ element, System::Windows::Input::ExecutedRoutedEventHandler ^ handler);

public static void AddExecutedHandler (System.Windows.UIElement element, System.Windows.Input.ExecutedRoutedEventHandler handler);

static member AddExecutedHandler : System.Windows.UIElement * System.Windows.Input.ExecutedRoutedEventHandler -> unit

Public Shared Sub AddExecutedHandler (element As UIElement, handler As ExecutedRoutedEventHandler)

Parameters

element

UIElement

The element to attach handler to.

handler

ExecutedRoutedEventHandler

The executed handler.

Exceptions

ArgumentNullException

element or handler is null.

Examples

The following example creates a CanExecuteRoutedEventHandler and an ExecutedRoutedEventHandler and attaches them to a Button which is a command source for the Help command.

First, the Button is created and associated with the Help command.

<Button Command="ApplicationCommands.Help"
        Name="helpButton">Help</Button>

Next, the CanExecuteRoutedEventHandler and the ExecutedRoutedEventHandler are created.

private void HelpCmdExecuted(object sender, ExecutedRoutedEventArgs e)
{
    // OpenHelpFile opens the help file
    OpenHelpFile();
}

Private Sub HelpCmdExecuted(ByVal sender As Object, ByVal e As ExecutedRoutedEventArgs)
    ' OpenHelpFile opens the help file
    OpenHelpFile()
End Sub

private void HelpCmdCanExecute(object sender, CanExecuteRoutedEventArgs e)
{
    // HelpFilesExists() determines if the help file exists
    if (HelpFileExists() == true)
    {
        e.CanExecute = true;
    }
    else
    {
        e.CanExecute = false;
    }
}

Private Sub HelpCmdCanExecute(ByVal sender As Object, ByVal e As CanExecuteRoutedEventArgs)
    ' HelpFilesExists() determines if the help file exists
    If HelpFileExists() = True Then
        e.CanExecute = True
    Else
        e.CanExecute = False
    End If
End Sub

And finally, the handlers are attached to the Button using the AddCanExecuteHandler and AddExecutedHandler.

CommandManager.AddExecutedHandler(helpButton, HelpCmdExecuted);
CommandManager.AddCanExecuteHandler(helpButton, HelpCmdCanExecute);

CommandManager.AddExecutedHandler(helpButton, AddressOf HelpCmdExecuted)
CommandManager.AddCanExecuteHandler(helpButton, AddressOf HelpCmdCanExecute)

See also

• RoutedCommand
• ICommand