Code

void ProcessDiagram_LinkCreated(object sender, LinkEventArgs e)
{
if (log.IsDebugEnabled)
log.Debug("Link Created");

if (e.Link != null)
{
CompositeCmd cmd = this.UndoManager.StartComposite("Change Link");

DiagramLink uiLink = e.Link;

ControlLink controlLink = new ControlLink(this);
controlLink.Origin = (AbstractNode)e.Link.Origin;
controlLink.Destination = (AbstractNode)e.Link.Destination;

// Link를 원하는 값으로 교체하기 위해서 DiagramLink Create Command를 Undo 한다.
//
UndoManager.Undo();

//if(this.Links.Contains(e.Link))
//{
//    this.Links.Remove(e.Link);
//    if (log.IsDebugEnabled)
//	  log.Debug("Default Link is deleted.");
//}

this.Links.Remove(e.Link);
this.Links.Add(controlLink);

cmd.Execute();
}
}