SelectionChangedEventArgs.InvokeEventHandler(Delegate, Object) 方法

定義

命名空間:

System.Windows.Controls

組件:

PresentationFramework.dll

執行適當的型別轉換，以呼叫 SelectionChangedEventHandler 事件的型別安全 SelectionChanged 委派。

protected:
 override void InvokeEventHandler(Delegate ^ genericHandler, System::Object ^ genericTarget);

protected override void InvokeEventHandler (Delegate genericHandler, object genericTarget);

override this.InvokeEventHandler : Delegate * obj -> unit

Protected Overrides Sub InvokeEventHandler (genericHandler As Delegate, genericTarget As Object)

參數

genericHandler

Delegate

要叫用 (Invoke) 的處理常式。

genericTarget

Object

目前在事件路徑上的物件。

範例

下列範例會 ListBox 建立 並訂閱 SelectionChanged 事件。 它會使用 SelectionChangedEventArgs ，在 中 ListBox 尋找選取的專案。

<WrapPanel Width="500" Orientation="Horizontal" Name="rectanglesPanel">
  <WrapPanel.Resources>
    <Style TargetType="Rectangle">
      <Setter Property="Height" Value="20"/>
      <Setter Property="Width" Value="20"/>
      <Setter Property="Margin" Value="5"/>
    </Style>
  </WrapPanel.Resources>
</WrapPanel>

<ListBox Name="myListBox" HorizontalAlignment="Left" SelectionMode="Extended" 
      Width="265" Height="55" Background="HoneyDew" SelectionChanged="myListBox_SelectionChanged"
      ItemsSource="{Binding Source={StaticResource Colors}}" IsSynchronizedWithCurrentItem="true">
</ListBox>

void myListBox_SelectionChanged(object sender, SelectionChangedEventArgs args)
{

    BrushConverter converter = new BrushConverter();

    // Show Rectangles that are the selected colors.
    foreach (string color in args.AddedItems)
    {
        if (GetRectangle(color) == null)
        {
            Rectangle aRect = new Rectangle();
            aRect.Fill = (Brush) converter.ConvertFrom(color);
            aRect.Tag = color;
            rectanglesPanel.Children.Add(aRect);
        }
    }

    // Remove the Rectangles that are the unselected colors.
    foreach (string color in args.RemovedItems)
    {
        FrameworkElement removedItem = GetRectangle(color);
        if (removedItem != null)
        {
            rectanglesPanel.Children.Remove(removedItem);
        }
    }
}

FrameworkElement GetRectangle(string color)
{
    foreach (FrameworkElement rect in rectanglesPanel.Children)
    {
        if (rect.Tag.ToString() == color)
            return rect;
    }

    return null;
}

Private Sub myListBox_SelectionChanged(ByVal sender As Object, ByVal args As SelectionChangedEventArgs)

    Dim converter As BrushConverter = New BrushConverter()
    Dim color As String

    ' Show Rectangles that are the selected colors.
    For Each color In args.AddedItems

        If GetRectangle(color) Is Nothing Then
            Dim aRect As Rectangle = New Rectangle()
            aRect.Fill = CType(converter.ConvertFrom(color), Brush)
            aRect.Tag = color
            rectanglesPanel.Children.Add(aRect)
        End If

    Next

    ' Remove the Rectangles that are the unselected colors.
    For Each color In args.RemovedItems

        Dim removedItem As FrameworkElement = GetRectangle(color)
        If Not removedItem Is Nothing Then
            rectanglesPanel.Children.Remove(removedItem)
        End If

    Next

End Sub

Private Function GetRectangle(ByVal color As String) As FrameworkElement
    Dim rect As FrameworkElement
    For Each rect In rectanglesPanel.Children
        If rect.Tag.ToString() = color Then
            Return rect
        End If
    Next

    Return Nothing
End Function

另請參閱

• SelectionChangedEventHandler