RoutedPropertyChangedEventHandler<T> 代理人

定義

命名空間:

System.Windows

組件:

PresentationFramework.dll

表示將處理各種追蹤屬性值變更之路由事件的方法。

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))

類型參數

T

屬性值的類型，其會報告該值的變更。

參數

sender

Object

附加事件處理常式的物件。

e

RoutedPropertyChangedEventArgs<T>

事件資料。 特定事件定義將會限制 RoutedPropertyChangedEventArgs<T> 為某類型，其中條件約束的型別參數符合委派實作的型別參數條件約束。

範例

下列範例會定義 並附加 事件的處理常式方法 ValueChanged 。

處理常式是以 為基礎 RoutedPropertyChangedEventHandler<T> ，而且定義于程式碼範例的第二個區段中，且泛型的類型參數限制為 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

這個特定範例不會使用 事件的 routed-event 特性;事件會在引發事件的相同專案上處理。 這不一定是這種情況。 對於路由事件，事件的來源可能與附加處理常式的物件不同。

備註

根據 RoutedPropertyChangedEventHandler<T> include TreeView.SelectedItemChanged 和 RangeBase.ValueChanged ，使用型別限制委派的事件範例。

擴充方法

另請參閱

• RoutedPropertyChangedEventArgs<T>