記錄一個問題，在此感謝同事( 拚忘 - 部落格園 )提供的編碼方案

問題：如下圖所示 需要支援觸控(或滑鼠)按壓在1上支援滑動操作，目前僅僅在2上可以滑動操作，1上只能點選操作無法滑動。 

1 Slider滑動條支援拖動，需要將move事件轉換觸發PreviewMouseLeftButtonDownEvent事件模擬滑動操作。 

2 捕捉裝置，鎖定在當前Slider上

解決方案：

第一步 建立SliderAttach

 public static class SliderAttach
    {
        public static bool GetMoveToPointOnDrag(DependencyObject obj) { return
 
 (bool)obj.GetValue(MoveToPointOnDragProperty); }
        public static void SetMoveToPointOnDrag(DependencyObject obj, bool value) { obj.SetValue(MoveToPointOnDragProperty, value); }

        /// <summary>
        /// 滾動條點選拖動附加屬性
        /// </summary>
        public static readonly DependencyProperty MoveToPointOnDragProperty = DependencyProperty.RegisterAttached("
 
MoveToPointOnDrag", typeof(bool), typeof(SliderAttach), new PropertyMetadata
        {
            PropertyChangedCallback = (obj, changeEvent) =>
            {
                var isDown = false;
                if (!(bool)changeEvent.NewValue) return;
                var slider = (Slider)obj;
                
 
if (!(slider.Parent is FrameworkElement parent)) return;

                parent.PreviewMouseDown += (sender, args) => { isDown = true; };
                slider.MouseMove += (obj2, mouseEvent) =>
                {
                    if (mouseEvent.LeftButton != MouseButtonState.Pressed || !isDown) return;
                    if (!slider.IsMouseCaptured) slider.CaptureMouse();
                    slider.RaiseEvent(new MouseButtonEventArgs(mouseEvent.MouseDevice, mouseEvent.Timestamp, MouseButton.Left)
                    {
                        RoutedEvent = UIElement.PreviewMouseLeftButtonDownEvent,
                        Source = mouseEvent.Source,
                    });
                };
                parent.PreviewMouseUp += (sender, args) =>
                {
                    isDown = false;
                    slider.ReleaseMouseCapture();
                };
            }
        });
    }

第二步： Slider 設定附件屬性

 <Slider  resources:SliderAttach.MoveToPointOnDrag="True"/>