GNAySolution

ComboBox不用取得邏輯焦點(!IsFocused)，只要滑鼠在ComboBox上方(IsMouseOver)，移動滾輪(MouseWheelEventArgs.Delta > 0 or < 0)，就能調整選項

延續之前的文章，ItemsControl.ItemsSource關聯字串(string)型態資料檢視，繼續以ComboBoxOrderBuySell作為範例介紹

MouseWheelEventArgs.Delta > 0，代表滑鼠滾輪向上滾(圖左，遠離使用者)，< 0，代表向下滾(圖右，靠近使用者)

XAML:
<Window <-- -->
        Title="MainWindow" Height="990" Width="1760" PreviewMouseWheel="Window_PreviewMouseWheel">
    <Grid>

<Label Content="Buy/Sell" HorizontalAlignment="Left" Margin="260,10,0,0" VerticalAlignment="Top"/>
<ComboBox x:Name="ComboBoxOrderBuySell" ToolTip="{Binding Path=SelectedValue, RelativeSource={RelativeSource Self}}" HorizontalAlignment="Left" Margin="260,35,0,0" VerticalAlignment="Top" Width="120" IsEditable="True"/>

C#:
void Window_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
    if (e.Delta == 0)
    {
        return;
    }

    ComboBox cb = null;

    if (ComboBoxOrderBuySell.IsMouseOver && !ComboBoxOrderBuySell.IsFocused)
    {
        cb = ComboBoxOrderBuySell;
    }
    //else if //其他的ComboBox

    if (cb == null)
    {
        return;
    }

    int nextIdx = cb.SelectedIndex + (e.Delta > 0 ? -1 : 1);

    if (nextIdx >= 0 && nextIdx < cb.Items.Count)
    {
        cb.SelectedIndex = nextIdx;
    }
}