WPF可搜索组合框中的导航

我有我的自定义组合框：

public class CustomComboBox : ComboBox
{
    protected override void OnSelectionChanged(SelectionChangedEventArgs e)
    {
        // allow to go into items using up and down arrows without causing the text change
        e.Handled = true;
    }
}

和xaml为：

<Window>
    <Grid>
        <wpfApplication1:CustomComboBox IsEditable="True" 
                  Width="200" 
                  Height="25" 
                  IsTextSearchEnabled="False" 
                  StaysOpenOnEdit="True"
                  x:Name="cb" 
                  PreviewTextInput="Cb_OnPreviewTextInput" 
                  ItemsSource="{Binding Projects}" 
                  Text="{Binding Text}"
                  SelectionChanged="Cb_OnSelectionChanged">
            <ComboBox.ItemsPanel>
                <ItemsPanelTemplate>
                    <VirtualizingStackPanel />
                </ItemsPanelTemplate>
            </ComboBox.ItemsPanel>
        </wpfApplication1:CustomComboBox>
    </Grid>
</Window>

---

但这并没有起作用。

最后编写了一个新模板，其中包含一个

列表视图

加上PreviewKeyDown中的自定义逻辑：

if (e.Key == Key.Up || e.Key == Key.Down)
{
    listView.Focus();
    listView.Items.MoveCurrentTo(listView.SelectedItem);

    if (e.Key == Key.Up)
        listView.Items.MoveCurrentToPrevious();
    else
        listView.Items.MoveCurrentToNext();

    listView.SelectedItem = listView.Items.CurrentItem;
    listView.ScrollIntoView(listView.Items.CurrentItem);

    e.Handled = true;

    return;
}

工作正常；）

protected override void OnPreviewKeyDown(KeyEventArgs e)
{
    if (_popup != null && e.Key == Key.Up || e.Key == Key.Down)
    {
        Dispatcher.BeginInvoke(DispatcherPriority.Input, 
        new Action(() =>
        {
            var c = _popup.Child;
            var vs = c.GetChildOfType<VirtualizingStackPanel>();
            vs.PageUp();
            vs.Focus();
            Keyboard.Focus(vs);
        }));
    }

    base.OnPreviewKeyDown(e);
}

if (e.Key == Key.Up || e.Key == Key.Down)
{
    listView.Focus();
    listView.Items.MoveCurrentTo(listView.SelectedItem);

    if (e.Key == Key.Up)
        listView.Items.MoveCurrentToPrevious();
    else
        listView.Items.MoveCurrentToNext();

    listView.SelectedItem = listView.Items.CurrentItem;
    listView.ScrollIntoView(listView.Items.CurrentItem);

    e.Handled = true;

    return;
}