CommandManager.AddCanExecuteHandler Yöntem

Tanım

Ad Alanı:

System.Windows.Input

Bütünleştirilmiş Kod:

PresentationCore.dll

Belirtilen öğesini belirtilen CanExecuteRoutedEventHandler öğeye ekler.

public:
 static void AddCanExecuteHandler(System::Windows::UIElement ^ element, System::Windows::Input::CanExecuteRoutedEventHandler ^ handler);

public static void AddCanExecuteHandler (System.Windows.UIElement element, System.Windows.Input.CanExecuteRoutedEventHandler handler);

static member AddCanExecuteHandler : System.Windows.UIElement * System.Windows.Input.CanExecuteRoutedEventHandler -> unit

Public Shared Sub AddCanExecuteHandler (element As UIElement, handler As CanExecuteRoutedEventHandler)

Parametreler

element

UIElement

Eklenecek handler öğe.

handler

CanExecuteRoutedEventHandler

, işleyici yürütebilir.

Özel durumlar

ArgumentNullException

element veya handler şeklindedir null.

Örnekler

Aşağıdaki örnek bir CanExecuteRoutedEventHandler ve ExecutedRoutedEventHandler oluşturur ve bunları komutun Help komut kaynağı olan öğesine Button ekler.

İlk olarak, Button komutu oluşturulur ve komutuyla ilişkilendirilir Help .

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

CanExecuteRoutedEventHandler Ardından ve ExecutedRoutedEventHandler oluşturulur.

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

Son olarak, işleyiciler ve AddExecutedHandlerkullanılarak AddCanExecuteHandler öğesine Button eklenir.

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

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

Ayrıca bkz.

• RoutedCommand
• ICommand