public void QueryAllowedDragPositions(QueryAllowedPositionsEventArgs args)
{
args.AllowedCopyPositions = DropLinePosition.None;
args.AllowedMovePositions = DropLinePosition.None;
DesignerNodeData sourceNodeData = args.Source as DesignerNodeData;
if (sourceNodeData != null)
{
INode source = sourceNodeData.TreeNode.Node;
INode target = ((DesignerNode)args.TargetNode).Node;
if (target.IsValidChild(source))
{
args.AllowedCopyPositions |= DropLinePosition.OnNode;
if (!IsNodeContained(source, target, true))
{
args.AllowedMovePositions |= DropLinePosition.OnNode;
}
}
if ((args.TargetNode.Parent != null) && target.Parent.IsValidChild(source))
{
args.AllowedCopyPositions |= (DropLinePosition.AboveNode | DropLinePosition.BelowNode);
if (!IsNodeContained(source, target.Parent, true) && !Object.ReferenceEquals(target, source))
{
int index = target.Parent.Children.IndexOf(target);
if
(
(index == 0) ||
((index > 0) && !ReferenceEquals(target.Parent.Children[index - 1], source))
)
{
args.AllowedMovePositions |= DropLinePosition.AboveNode;
}
if
(
(index == target.Parent.Children.Count - 1) ||
((index < target.Parent.Children.Count - 1) && !ReferenceEquals(target.Parent.Children[index + 1], source))
)
{
args.AllowedMovePositions |= DropLinePosition.BelowNode;
}
}
}
}
}
protected override void OnDragDrop(DragEventArgs args)
{
if (args.Effect != DragDropEffects.None)
{
try
{
base.OnDragDrop(args);
DesignerNodeData data = args.Data as DesignerNodeData;
if
(
(_dropFilter.DropHighlightNode != null) &&
(_dropFilter.DropLinePosition != DropLinePosition.None) &&
(data != null)
)
{
if (data.RightButton)
{
new DesignerTreeDropMenu(data.TreeNode, (DesignerNode)_dropFilter.DropHighlightNode, _dropFilter.DropLinePosition, _dropFilter.DropOperation).Show(this, PointToClient(Control.MousePosition));
}
else
{
if (Control.ModifierKeys == Keys.Control)
{
((DesignerNode)_dropFilter.DropHighlightNode).CopyFromNode(data.TreeNode, _dropFilter.DropLinePosition);
}
else
{
((DesignerNode)_dropFilter.DropHighlightNode).MoveFromNode(data.TreeNode, _dropFilter.DropLinePosition);
}
}
}
EndDrag();
}
catch (Exception exception)
{
// must handle exceptions because the framework ignores them
FormDesigner.Dataphoria.Warnings.AppendError(FormDesigner, exception, false);
// do not re-throw
}
}
}
