RoutedPropertyChangedEventHandler<T> Delegato

Definizione

generic <typename T>
public delegate void RoutedPropertyChangedEventHandler(System::Object ^ sender, RoutedPropertyChangedEventArgs<T> ^ e);

public delegate void RoutedPropertyChangedEventHandler<T>(object sender, RoutedPropertyChangedEventArgs<T> e);

type RoutedPropertyChangedEventHandler<'T> = delegate of obj * RoutedPropertyChangedEventArgs<'T> -> unit

Public Delegate Sub RoutedPropertyChangedEventHandler(Of T)(sender As Object, e As RoutedPropertyChangedEventArgs(Of T))

Parametri di tipo

Parametri

Ereditarietà

Object

Delegate

RoutedPropertyChangedEventHandler<T>

Esempio

Nell'esempio seguente viene definito e collegato un metodo del gestore per l' ValueChanged evento.The following example defines and attaches a handler method for the ValueChanged event.

Il gestore si basa su RoutedPropertyChangedEventHandler<T> e viene definito nel secondo segmento dell'esempio di codice, con il parametro di tipo dell'oggetto generico vincolato a Double .The handler is based on RoutedPropertyChangedEventHandler<T>, and is defined in the second segment of the code example, with the type parameter of the generic constrained to Double.

Slider childrenCountSlider = (Slider)LogicalTreeHelper.FindLogicalNode(myWindow, "ChildrenCountSlider");
childrenCountSlider.ValueChanged += new RoutedPropertyChangedEventHandler<double>(OnChildrenCountChanged);

Dim childrenCountSlider As Slider = CType(LogicalTreeHelper.FindLogicalNode(myWindow, "ChildrenCountSlider"), Slider)
AddHandler childrenCountSlider.ValueChanged, AddressOf OnChildrenCountChanged

private void OnChildrenCountChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
    int childrenCount = (int)Math.Floor(e.NewValue + 0.5);

    //  Update the children count...
    AutoIndexingGrid g = (AutoIndexingGrid)LogicalTreeHelper.FindLogicalNode(myWindow, "TargetGrid");
    while (g.Children.Count < childrenCount)
    {
        Control c = new Control();
        g.Children.Add(c);
        c.Style = (Style)c.FindResource("ImageWithBorder");
    }
    while (g.Children.Count > childrenCount)
    {
        g.Children.Remove(g.Children[g.Children.Count - 1]);
    }


    //  Update TextBlock element displaying the count...
    TextBlock t = (TextBlock)LogicalTreeHelper.FindLogicalNode(myWindow, "ChildrenCountDisplay");
    t.Text = childrenCount.ToString();
}

Private Sub OnChildrenCountChanged(ByVal sender As Object, ByVal e As RoutedPropertyChangedEventArgs(Of Double))
    Dim childrenCount As Integer = CInt(Fix(Math.Floor(e.NewValue + 0.5)))

    '  Update the children count...
    Dim g As AutoIndexingGrid = CType(LogicalTreeHelper.FindLogicalNode(myWindow, "TargetGrid"), AutoIndexingGrid)
    Do While g.Children.Count < childrenCount
        Dim c As New Control()
        g.Children.Add(c)
        c.Style = CType(c.FindResource("ImageWithBorder"), Style)
    Loop
    Do While g.Children.Count > childrenCount
        g.Children.Remove(g.Children(g.Children.Count - 1))
    Loop


    '  Update TextBlock element displaying the count...
    Dim t As TextBlock = CType(LogicalTreeHelper.FindLogicalNode(myWindow, "ChildrenCountDisplay"), TextBlock)
    t.Text = childrenCount.ToString()
End Sub

Questo particolare esempio non usa la caratteristica dell'evento indirizzato dell'evento. l'evento viene gestito sullo stesso elemento su cui è stato generato.This particular example does not use the routed-event characteristic of the event; the event is handled on the same element that it is raised on. Questo non è sempre il caso.This is not always the case. Per un evento indirizzato, è possibile che l'origine dell'evento sia un oggetto diverso rispetto all'oggetto a cui è associato il gestore.For a routed event, it is possible that the source of the event is a different object than the object where the handler is attached.

Commenti

Esempi di eventi che usano delegati con vincoli di tipo basati su RoutedPropertyChangedEventHandler<T> includono TreeView.SelectedItemChanged e RangeBase.ValueChanged .Examples of events that use type-constrained delegates based on RoutedPropertyChangedEventHandler<T> include TreeView.SelectedItemChanged and RangeBase.ValueChanged.

Metodi di estensione

Si applica a

Vedi anche

• RoutedPropertyChangedEventArgs<T>