//
// OnDragOver event handler. Updates the dragged node's ghost image's position
//
protected override void OnDragOver(DragEventArgs drgevent)
{
base.OnDragOver(drgevent);
// Cancel if no node is being dragged
if (_draggedItems == null)
{
return;
}
// Get actual drop item
Point controlP = PointToClient(new Point(drgevent.X, drgevent.Y));
int index = InsertionMark.NearestIndex(controlP);
if (index == -1)
{
return;
}
InsertionMark.Index = index;
ListViewItem dropItem = Items[index];//GetItemAt(controlP.X, controlP.Y);
if (dropItem != _tempDropItem)
{
ListViewItemDragEventArgs evArgs = new ListViewItemDragEventArgs(ListViewItemDragEventType.DragOver, ListViewItemDragEventBehavior.PlaceBeforeOrAfterAuto, _draggedItems, dropItem);
if (DragOperation != null)
{
DragOperation(evArgs);
// Cancel the operation if the user specified so
if (evArgs.Cancel)
{
drgevent.Effect = DragDropEffects.None;
OnDragDrop(drgevent);
return;
}
if (!evArgs.Allow)
{
return;
}
}
drgevent.Effect = DragDropEffects.Move;
// Dissalow the drag here
if (!evArgs.Allow)
{
drgevent.Effect = DragDropEffects.None;
}
_tempDropItem = dropItem;
}
}
public DragDropAssist(ListView listView)
{
fListView = listView;
fInsertionMark = new InsertionMark(fListView);
fListView.PreviewMouseLeftButtonDown += ListView_PreviewMouseLeftButtonDown;
fListView.PreviewMouseLeftButtonUp += ListView_PreviewMouseLeftButtonUp;
fListView.PreviewMouseMove += ListView_PreviewMouseMove;
fListView.DragOver += ListView_DragOver;
fListView.Drop += ListView_Drop;
fListView.QueryContinueDrag += ListView_QueryContinueDrag;
fListView.AllowDrop = true;
}
private void lv_DragOver(object sender, DragEventArgs e)
{
Point targetPoint = PointToClient(new Point(e.X, e.Y));
int targetIndex = InsertionMark.NearestIndex(targetPoint);
if (targetIndex > -1)
{
Rectangle itemBounds = GetItemRect(targetIndex);
EnsureVisible(targetIndex);
if (targetPoint.Y > itemBounds.Top + (itemBounds.Height / 2))
{
InsertionMark.AppearsAfterItem = true;
}
else
{
InsertionMark.AppearsAfterItem = false;
}
}
InsertionMark.Index = targetIndex;
}
protected override void OnDragOver(DragEventArgs drgevent)
{
base.OnDragOver(drgevent);
Point ptScreen = new Point(drgevent.X, drgevent.Y);
Point pt = PointToClient(ptScreen);
ListViewItem item = GetItemAt(pt.X, pt.Y);
int targetIndex = InsertionMark.NearestIndex(pt);
if (targetIndex > -1)
{
Rectangle itemBounds = GetItemRect(targetIndex);
if (pt.X > itemBounds.Left + (itemBounds.Width / 2))
{
InsertionMark.AppearsAfterItem = true;
}
else
{
InsertionMark.AppearsAfterItem = false;
}
}
InsertionMark.Index = targetIndex;
}
