CommandManager.AddPreviewExecutedHandler(UIElement, ExecutedRoutedEventHandler) Yöntem

Tanım

Belirtilen öğeye belirtilen ExecutedRoutedEventHandler öğesi ekler.Attaches the specified ExecutedRoutedEventHandler to the specified element.

public:
 static void AddPreviewExecutedHandler(System::Windows::UIElement ^ element, System::Windows::Input::ExecutedRoutedEventHandler ^ handler);
public static void AddPreviewExecutedHandler (System.Windows.UIElement element, System.Windows.Input.ExecutedRoutedEventHandler handler);
static member AddPreviewExecutedHandler : System.Windows.UIElement * System.Windows.Input.ExecutedRoutedEventHandler -> unit
Public Shared Sub AddPreviewExecutedHandler (element As UIElement, handler As ExecutedRoutedEventHandler)

Parametreler

element
UIElement

İliştiriedilecek öğe handler .The element to attach handler to.

handler
ExecutedRoutedEventHandler

, İşleyiciyi yürütebilirler.The can execute handler.

Özel durumlar

elementya handler da null .element or handler is null.

Örnekler

Aşağıdaki örnek bir ve oluşturur CanExecuteRoutedEventHandler ExecutedRoutedEventHandler ve bunları Button komut için bir komut kaynağı olan öğesine ekler Help .The following example creates a CanExecuteRoutedEventHandler and an ExecutedRoutedEventHandler and attaches them to a Button which is a command source for the Help command.

İlk olarak, Button oluşturulur ve Help komutla ilişkilendirilir.First, the Button is created and associated with the Help command.

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

Ardından, CanExecuteRoutedEventHandler ve ExecutedRoutedEventHandler oluşturulur.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

Son olarak, işleyiciler ve kullanarak öğesine eklenir Button AddCanExecuteHandler AddExecutedHandler .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)

Şunlara uygulanır

Ayrıca bkz.