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CommandManager.AddExecutedHandler Metodo

  • Riferimento

Definizione

Spazio dei nomi:
System.Windows.Input
Assembly:
PresentationCore.dll

Associa l'oggetto ExecutedRoutedEventHandler specificato all'elemento specificato.

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)

Parametri

element
UIElement

L'elemento a cui associare handler.

handler
ExecutedRoutedEventHandler

Il gestore eseguito.

Eccezioni

ArgumentNullException

element o handler è null.

Esempio

L'esempio seguente crea un CanExecuteRoutedEventHandler oggetto e ExecutedRoutedEventHandler li associa a un Button oggetto che è un'origine comando per il Help comando.

Prima di tutto, viene Button creato e associato al Help comando.

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

Successivamente, vengono creati i metodi CanExecuteRoutedEventHandler e ExecutedRoutedEventHandler.

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

Infine, i gestori sono collegati all'uso di ButtonAddCanExecuteHandler e AddExecutedHandler.

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

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

Si applica a

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