RoutedPropertyChangedEventHandler(Of T) Delegate
Represents methods that will handle various routed events that track property value changes.
Assembly: PresentationFramework (in PresentationFramework.dll)
'Declaration Public Delegate Sub RoutedPropertyChangedEventHandler(Of T) ( _ sender As Object, _ e As RoutedPropertyChangedEventArgs(Of T) _ )
The type of the property value where changes in value are reported.
- Type: System.Object
The object where the event handler is attached.
The following example defines and attaches a handler method for the ValueChanged event.
The handler is based on , and is defined in the second segment of the code example, with the type parameter of the generic constrained to Double.
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
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. This is not always the case. 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.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)