如何单独拖动 SelectedItem 附近的列表框项目

Question

我想拖动列表框选定的项目。拖动功能工作正常。我的要求是从列表框中的任何其他位置开始拖动时不应发生拖动。我已经这样做了，但这不起作用。请任何人建议我实现这一目标，

        private bool IsDragging { get; set; }

        private Point _startPoint { get; set; }        

        protected override void OnAttached()

        {                            

            this.AssociatedObject.PreviewMouseLeftButtonDown += AssociatedObject_PreviewMouseLeftButtonDown;

            this.AssociatedObject.PreviewMouseMove += AssociatedObject_PreviewMouseMove;

        }

        private void AssociatedObject_PreviewMouseMove(object sender, MouseEventArgs e)

        {

            if (e.LeftButton == MouseButtonState.Pressed && !IsDragging)

            {

                Point position = e.GetPosition(null);                      

                if (Math.Abs(position.X - _startPoint.X) <= SystemParameters.MinimumHorizontalDragDistance &&

                    Math.Abs(position.Y - _startPoint.Y) <= SystemParameters.MinimumVerticalDragDistance)

                {

                    StartDrag(sender);

                }

            }

        }

        private void AssociatedObject_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)

        {

            _startPoint = e.GetPosition(null);

        }

        private void StartDrag(object sender)

        {

            IsDragging = true;

            if (sender is ListBox)

            {

                var listBox = (sender as ListBox);

                if (listBox != null)

                {

                    var selectedMember = listBox.SelectedItem;

                    if (selectedMember != null)

                    {

                        DragDrop.DoDragDrop(listBox, selectedMember, DragDropEffects.Copy);

                    }

                }

            }

            IsDragging = false;

        }

Answer 1

这样做，通过使用System.Windows.Media.VisualTreeHelper.HitTest(this, point)它给出鼠标下的当前元素。我想它会帮助你。private bool IsDrag { get; set; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; protected override void OnAttached()&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; this.AssociatedObject.Drop += AssociatedObject_Drop;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; this.AssociatedObject.PreviewMouseLeftButtonDown += AssociatedObject_PreviewMouseLeftButtonDown;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; this.AssociatedObject.PreviewMouseMove += AssociatedObject_PreviewMouseMove;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; private void AssociatedObject_PreviewMouseMove(object sender, MouseEventArgs e)&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (e.LeftButton == MouseButtonState.Pressed)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(IsDrag)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; StartDrag(sender);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; private void AssociatedObject_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; IsDrag = false;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(sender is ListBox)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Point initialPoint = e.GetPosition((UIElement)sender);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var histPoint = VisualTreeHelper.HitTest(sender as ListBox, initialPoint);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (histPoint.VisualHit != null)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (histPoint.VisualHit is TextBlock || histPoint.VisualHit is Border)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; IsDrag = true;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; private void StartDrag(object sender)&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (sender is ListBox)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var listBox = (sender as ListBox);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (listBox != null)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var selectedMember = listBox.SelectedItem;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (selectedMember != null)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; DragDrop.DoDragDrop(listBox, selectedMember, DragDropEffects.Copy);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; }