//
// OnDragDrop event handler. Ends a node dragging
//
protected override void OnDragDrop(DragEventArgs drgevent)
{
base.OnDragDrop(drgevent);
// Cancel if no node is being dragged
if (_draggedNode == null)
{
return;
}
// Unlock updates
DragHelper.ImageList_DragLeave(Handle);
if (drgevent.Effect == DragDropEffects.None)
{
// Set drag node and temp drop node to null
_draggedNode = null;
_tempDropNode = null;
// Disable scroll timer
_timer.Enabled = false;
return;
}
// Get drop node
TreeNode dropNode = GetNodeAt(PointToClient(new Point(drgevent.X, drgevent.Y)));
// Launch the feedback for the drag operation
TreeViewNodeDragEventArgs evArgs = new TreeViewNodeDragEventArgs(TreeViewNodeDragEventType.DragEnd, TreeViewNodeDragEventBehavior.PlaceInside, _draggedNode, dropNode);
if (DragOperation != null)
{
DragOperation(evArgs);
// Cancel the operation if the user specified so
if (evArgs.Cancel)
{
return;
}
}
// If drop node isn't equal to drag node, add drag node as child of drop node
if (_draggedNode != dropNode)
{
// Remove drag node from parent
if (_draggedNode.Parent == null)
{
Nodes.Remove(_draggedNode);
}
else
{
_draggedNode.Parent.Nodes.Remove(_draggedNode);
}
// Place the dragged node before or after the target node depending on mouse position
if (evArgs.EventBehavior == TreeViewNodeDragEventBehavior.PlaceBeforeOrAfterAuto)
{
// Get drop node
Point mouseP = PointToClient(MousePosition);
// Figure out whether the node should be added uder or over the pointed item by checking if the mouse is under or over the middle of the item
evArgs.EventBehavior = mouseP.Y > dropNode.Bounds.Y + dropNode.Bounds.Height / 2
? TreeViewNodeDragEventBehavior.PlaceAfter
: TreeViewNodeDragEventBehavior.PlaceBefore;
}
// Place the dragged node before the target node
if (evArgs.EventBehavior == TreeViewNodeDragEventBehavior.PlaceBefore)
{
// Add drag node before drop node
if (dropNode.Parent != null)
{
dropNode.Parent.Nodes.Insert(dropNode.Index, _draggedNode);
}
else
{
Nodes.Insert(dropNode.Index, _draggedNode);
}
SelectedNode = _draggedNode;
}
// Place the dragged node after the target node
if (evArgs.EventBehavior == TreeViewNodeDragEventBehavior.PlaceAfter)
{
// Add drag node after drop node
if (dropNode.Parent != null)
{
dropNode.Parent.Nodes.Insert(dropNode.Index + 1, _draggedNode);
}
else
{
Nodes.Insert(dropNode.Index + 1, _draggedNode);
}
SelectedNode = _draggedNode;
}
// Place the dragged node inside the target node
if (evArgs.EventBehavior == TreeViewNodeDragEventBehavior.PlaceInside)
{
// Add drag node to drop node
dropNode.Nodes.Add(_draggedNode);
dropNode.ExpandAll();
}
// Launch the feedback for the drag operation
evArgs = new TreeViewNodeDragEventArgs(TreeViewNodeDragEventType.AfterDragEnd, evArgs.EventBehavior, _draggedNode, dropNode);
DragOperation?.Invoke(evArgs);
// Set drag node and temp drop node to null
_draggedNode = null;
_tempDropNode = null;
// Disable scroll timer
_timer.Enabled = false;
}
}
//
// OnDragDrop event handler. Ends a node dragging
//
protected override void OnDragDrop(DragEventArgs drgevent)
{
base.OnDragDrop(drgevent);
// Cancel if no node is being dragged
if (_draggedItems == null)
{
_timer.Start();
return;
}
if (drgevent.Effect == DragDropEffects.None)
{
// Set drag node and temp drop node to null
_draggedItems = null;
_tempDropItem = null;
// Disable scroll timer
_timer.Enabled = false;
_timer.Start();
return;
}
if (InsertionMark.Index == -1)
{
_timer.Start();
return;
}
// Get drop item
ListViewItem dropItem = Items[InsertionMark.Index];
// Launch the feedback for the drag operation
ListViewItemDragEventArgs evArgs = new ListViewItemDragEventArgs(ListViewItemDragEventType.DragEnd, ListViewItemDragEventBehavior.PlaceBeforeOrAfterAuto, _draggedItems, dropItem);
if (DragOperation != null)
{
DragOperation(evArgs);
// Cancel the operation if the user specified so
if (evArgs.Cancel)
{
_timer.Start();
return;
}
}
// If drop node isn't equal to drag node, add drag node as child of drop node
if (_draggedItems[0] != dropItem)
{
int index = InsertionMark.Index;
SelectedItems.Clear();
foreach (ListViewItem item in _draggedItems)
{
Items.Remove(item);
Items.Add(item);
item.Selected = true;
}
// Deal with a bug from the framework that adds all items to the end even though you insert
// them at other indexes by also pushing all items after the current selection to the end
for (int i = index; i < Items.Count - SelectedItems.Count; i++)
{
ListViewItem item = Items[index];
Items.Remove(item);
Items.Add(item);
}
// Launch the feedback for the drag operation
evArgs = new ListViewItemDragEventArgs(ListViewItemDragEventType.AfterDragEnd, evArgs.EventBehavior, _draggedItems, dropItem);
DragOperation?.Invoke(evArgs);
// Set drag node and temp drop node to null
_draggedItems = null;
_tempDropItem = null;
// Disable scroll timer
_timer.Enabled = false;
}
_timer.Start();
}