public void DiscoverTreeEdge(object sender, EdgeEdgeEventArgs args)
 {
     if (args.get_Edge() != args.get_TargetEdge())
     {
         this.EdgePredecessors.set_Item(args.get_TargetEdge(), args.get_Edge());
     }
 }
 public void RecordSource(object sender, EdgeEdgeEventArgs args)
 {
     this.Edges.Add(args.get_Edge());
 }