/// <summary>
/// The dragging tool is applicable when the user can move or copy one or more objects.
/// </summary>
/// <returns>
/// This predicate returns true when:
/// <list type="bullet">
/// <item>the user has started moving the mouse with a mouse button down</item>
/// <item>the view allows objects to be moved or copied or dragged out of the window</item>
/// <item>the mouse button is not the context menu button</item>
/// <item>there is a selectable object under the mouse</item>
/// <item>and that object can be moved or copied</item>
/// </list>
/// </returns>
public override bool CanStart()
{
if (!base.View.CanMoveObjects() && !base.View.CanCopyObjects() && !base.View.AllowDragOut)
{
return(false);
}
if (base.LastInput.IsContextButton)
{
return(false);
}
if (!IsBeyondDragSize())
{
return(false);
}
GoObject goObject = base.View.PickObject(doc: true, view: false, base.FirstInput.DocPoint, selectableOnly: true);
if (goObject == null)
{
return(false);
}
if (!goObject.CanMove() && !goObject.CanCopy())
{
return(false);
}
return(true);
}
/// <summary>
/// Produce a new <see cref="T:Northwoods.Go.GoSelection" /> that is the real set of objects
/// to be moved by <see cref="M:Northwoods.Go.GoView.MoveSelection(Northwoods.Go.GoSelection,System.Drawing.SizeF,System.Boolean)" /> or copied by
/// <see cref="M:Northwoods.Go.GoView.CopySelection(Northwoods.Go.GoSelection,System.Drawing.SizeF,System.Boolean)" />.
/// </summary>
/// <param name="coll"></param>
/// <param name="move">true for moving, false for copying</param>
/// <returns>a <see cref="T:Northwoods.Go.GoSelection" /> that is cached as <see cref="P:Northwoods.Go.GoToolDragging.EffectiveSelection" /></returns>
/// <remarks>
/// This method is used to try to avoid problems with double-moving
/// due to duplicate entries or both a parent and its child being in
/// the argument collection.
/// This also removes objects whose <see cref="P:Northwoods.Go.GoObject.DraggingObject" />
/// is null or has a false value for <see cref="M:Northwoods.Go.GoObject.CanMove" /> (if
/// <paramref name="move" /> is true) or a false value for <see cref="M:Northwoods.Go.GoObject.CanCopy" />
/// (if <paramref name="move" /> is false).
/// Furthermore this adds to the collection all links that have both
/// ports in the selection.
/// </remarks>
public virtual GoSelection ComputeEffectiveSelection(IGoCollection coll, bool move)
{
Dictionary <GoObject, bool> dictionary = new Dictionary <GoObject, bool>();
GoCollection goCollection = null;
GoSelection goSelection = new GoSelection(null);
foreach (GoObject item in coll)
{
GoObject draggingObject = item.DraggingObject;
if (draggingObject != null && !(move ? (!draggingObject.CanMove()) : (!draggingObject.CanCopy())) && !alreadyDragged(dictionary, draggingObject))
{
dictionary[draggingObject] = true;
if (!draggingObject.IsTopLevel)
{
if (goCollection == null)
{
goCollection = new GoCollection();
}
goCollection.Add(draggingObject);
}
goSelection.Add(draggingObject);
}
}
if (EffectiveSelectionIncludesLinks)
{
GoObject[] array = goSelection.CopyArray();
for (int i = 0; i < array.Length; i++)
{
IGoNode goNode = array[i] as IGoNode;
if (goNode != null)
{
foreach (IGoLink destinationLink in goNode.DestinationLinks)
{
if (!alreadyDragged(dictionary, destinationLink.GoObject) && (destinationLink.ToPort == null || alreadyDragged(dictionary, destinationLink.ToPort.GoObject)))
{
dictionary[destinationLink.GoObject] = true;
goSelection.Add(destinationLink.GoObject);
}
}
foreach (IGoLink sourceLink in goNode.SourceLinks)
{
if (!alreadyDragged(dictionary, sourceLink.GoObject) && (sourceLink.FromPort == null || alreadyDragged(dictionary, sourceLink.FromPort.GoObject)))
{
dictionary[sourceLink.GoObject] = true;
goSelection.Add(sourceLink.GoObject);
}
}
}
}
}
if (goCollection != null)
{
GoCollection goCollection2 = null;
foreach (GoObject item2 in goSelection)
{
GoObject draggingObject2 = item2.DraggingObject;
if (draggingObject2 is GoGroup)
{
foreach (GoObject item3 in goCollection)
{
if (item3.IsChildOf(draggingObject2))
{
if (goCollection2 == null)
{
goCollection2 = new GoCollection();
}
goCollection2.Add(item3);
}
}
}
}
if (goCollection2 != null)
{
foreach (GoObject item4 in goCollection2)
{
goSelection.Remove(item4);
}
return(goSelection);
}
}
return(goSelection);
}