SelectionChangedEventArgs(RoutedEvent, IList, IList) 构造函数

定义

命名空间:

System.Windows.Controls

程序集:

PresentationFramework.dll

初始化 SelectionChangedEventArgs 类的新实例。

public:
 SelectionChangedEventArgs(System::Windows::RoutedEvent ^ id, System::Collections::IList ^ removedItems, System::Collections::IList ^ addedItems);

public SelectionChangedEventArgs (System.Windows.RoutedEvent id, System.Collections.IList removedItems, System.Collections.IList addedItems);

new System.Windows.Controls.SelectionChangedEventArgs : System.Windows.RoutedEvent * System.Collections.IList * System.Collections.IList -> System.Windows.Controls.SelectionChangedEventArgs

Public Sub New (id As RoutedEvent, removedItems As IList, addedItems As IList)

参数

id

RoutedEvent

事件标识符 (ID) 。

removedItems

IList

在发生此事件期间，未选定的项。

addedItems

IList

在发生此事件期间，选定的项。

示例

以下示例创建 ListBox 并订阅 事件 SelectionChanged 。 它使用 SelectionChangedEventArgs 在 中 ListBox查找所选项。

<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