private void AdjustPotentialDropTarget(
DragQuery request,
DragQueryResult result)
{
if (result.IsDropPointInTheUpperHalfOfDropTarget)
{
result.HowToDrop = DropTargetInfo.DropBeforeTarget;
}
else
{
result.HowToDrop = DropTargetInfo.DropAfterTarget;
}
result.AdjustDropOnSeparator();
if (request.CanDropHere(result))
{
return;
}
if (request.IsDropPointAboveDragStartPoint)
{
result.HowToDrop = DropTargetInfo.DropBeforeTarget;
result.AdjustDropOnSeparator();
while (result.DropTarget != null &&
!request.CanDropHere(result))
{
result.DropTarget = result.DropTarget.Prev;
result.AdjustDropOnSeparator();
}
if (result.DropTarget == null)
{
return;
}
}
else
{
result.HowToDrop = DropTargetInfo.DropAfterTarget;
result.AdjustDropOnSeparator();
while (result.DropTarget != null &&
!request.CanDropHere(result))
{
result.DropTarget = result.DropTarget.Next;
result.AdjustDropOnSeparator();
}
if (result.DropTarget == null)
{
return;
}
}
}
public DragQueryResult CanAcceptBlocks(DragQuery draggedBlocks)
{
if (!CanTheoreticallyAcceptBlocks(draggedBlocks) ||
!this.MyControl.Bounds.HitTest(draggedBlocks.DropPoint))
{
return(null);
}
DragQueryResult result = FindAPlaceToDrop(draggedBlocks);
if (result != null && draggedBlocks.IsTargetNearSource(result))
{
return(null);
}
return(result);
}
private DragQueryResult CanDropAt(Block current)
{
IPotentialDropTarget target = current as IPotentialDropTarget;
if (target == null)
{
return(null);
}
DragQueryResult result = target.CanAcceptBlocks(DragState.Query);
if (result != null)
{
result.DropTargetContainer = target;
}
return(result);
}
public void AcceptBlocks(DragQuery draggedBlocks, DragQueryResult whereTo)
{
if (whereTo.DropTargetContainer.CanAcceptBlocks(draggedBlocks) == null)
{
return;
}
IEnumerable <Block> toDrop;
if (draggedBlocks.ShouldCopyInsteadOfMove)
{
toDrop = BlockActions.Clone(draggedBlocks);
toDrop = IntersperseWithSeparators(toDrop, whereTo);
if (whereTo.HowToDrop == DropTargetInfo.DropBeforeTarget)
{
whereTo.DropTarget.PrependBlocks(toDrop);
}
else
{
whereTo.DropTarget.AppendBlocks(toDrop);
}
}
else
{
using (Root.Transaction())
{
foreach (Block b in draggedBlocks)
{
b.Delete();
}
toDrop = IntersperseWithSeparators(draggedBlocks, whereTo);
if (whereTo.HowToDrop == DropTargetInfo.DropBeforeTarget)
{
whereTo.DropTarget.PrependBlocks(toDrop);
}
else
{
whereTo.DropTarget.AppendBlocks(toDrop);
}
}
}
}
private void Draw(IRenderer renderer)
{
//if (this.CurrentSelection != null)
//{
// Renderer.DrawOperations.DrawRectangle(
// CurrentSelection.Bounds,
// Color.Blue,
// 3);
//}
if (DragState != null)
{
DragQuery query = DragState.Query;
if (DragState.DragStarted)
{
dragRect.Location.Set(
DragState.Query.DropPoint + 24);
renderer.DrawOperations.DrawDotRectangle(
dragRect,
Color.DarkGray);
}
if (DragState.Result != null)
{
DragQueryResult result = DragState.Result;
dropRect.Set(result.DropTarget.MyControl.Bounds.AddMargins(
result.DropTarget.MyControl.Box.MouseSensitivityArea));
if (result.HowToDrop == DropTargetInfo.DropBeforeTarget)
{
dropRect.Size.Y = 3;
}
else if (result.HowToDrop == DropTargetInfo.DropAfterTarget)
{
dropRect.Location.Y += dropRect.Size.Y;
dropRect.Size.Y = 3;
}
renderer.DrawOperations.DrawRectangle(
dropRect,
Color.DeepSkyBlue, 2);
}
}
}
public DragQueryResult FindDropTarget()
{
Block current = FindBlockAtPoint(
DragState.Query.DropPoint.X,
DragState.Query.DropPoint.Y);
if (current == null)
{
return(null);
}
if (IsTargetWithinSource(current))
{
return(null);
}
DragQueryResult result = CanDropAt(current);
while (current != null && result == null)
{
current = current.Parent;
result = CanDropAt(current);
}
return(result);
}
public IEnumerable <Block> IntersperseWithSeparators(IEnumerable <Block> draggedBlocks, DragQueryResult whereTo)
{
List <Block> blocks = new List <Block>();
bool weHaveSeparators = HasSeparators;
foreach (Block dragged in draggedBlocks)
{
if (dragged is ISeparatorBlock)
{
if (weHaveSeparators)
{
blocks.Add(CreateSeparator());
}
}
else
{
if (blocks.Count > 0 &&
!(blocks[blocks.Count - 1] is ISeparatorBlock) &&
weHaveSeparators)
{
blocks.Add(CreateSeparator());
}
blocks.Add(dragged);
}
}
if (blocks.Count > 0 &&
!(blocks[blocks.Count - 1] is ISeparatorBlock) &&
weHaveSeparators)
{
blocks.Add(CreateSeparator());
}
return(blocks);
}
public virtual DragQueryResult FindAPlaceToDrop(DragQuery draggedBlocks)
{
Point dropPoint = draggedBlocks.DropPoint;
Block foundReferenceBlock = null;
DragQueryResult result;
int minDistance = int.MaxValue;
int distance;
if (this.Orientation == OrientationType.Horizontal)
{
foreach (Block child in this.Children)
{
if (!child.MyControl.Bounds.HitTestWithMarginX(
dropPoint.X,
child.MyControl.Box.MouseSensitivityArea))
{
continue;
}
if (child is ISeparatorBlock)
{
return(new DragQueryResult(child, DropTargetInfo.DropAfterSeparator));
}
else
{
distance = child.MyControl.Bounds.CenterX - dropPoint.X;
if (Math.Abs(distance) < Math.Abs(minDistance))
{
minDistance = distance;
foundReferenceBlock = child;
}
}
}
}
else
{
foreach (Block child in this.Children)
{
if (!child.MyControl.Bounds.HitTestWithMarginY(
dropPoint.Y,
child.MyControl.Box.MouseSensitivityArea))
{
continue;
}
if (child is ISeparatorBlock)
{
return(new DragQueryResult(child, DropTargetInfo.DropAfterSeparator));
}
else
{
distance = child.MyControl.Bounds.CenterY - dropPoint.Y;
if (Math.Abs(distance) < Math.Abs(minDistance))
{
minDistance = distance;
foundReferenceBlock = child;
}
}
}
}
if (foundReferenceBlock == null)
{
return(null);
}
result = new DragQueryResult(foundReferenceBlock);
result.IsDropPointInTheUpperHalfOfDropTarget = minDistance > 0;
AdjustPotentialDropTarget(draggedBlocks, result);
if (result.DropTarget == null)
{
return(null);
}
return(result);
}
