Code (C++)

case "Orthogonal":
                {
                    OrthogonalLayout layout = new OrthogonalLayout();
                    layout.Padding = 25;
                    layout.Arrange(diagram);
                    OrthogonalRouter layout2 = new OrthogonalRouter();
                    layout2.Arrange(diagram);
                    MirrorVertically(diagram);  // Increase the likelihood of the start shape being at the top of the diagram
                    setLinksToSingleSegment(diagram);  // Make the text on the links be center'd
                    fixSelfLoopBackLinks(diagram); // Draws a more attractive (bezier curve)
                    break;
                } 

Code (C++)

protected void MirrorVertically(Diagram diagram)
    {
        // Adapted from code provided by MF

        var bounds = diagram.GetContentBounds(false, true);
        var y = bounds.Y + bounds.Height / 2;
        foreach (DiagramNode node in diagram.Nodes)
        {
            var ny = node.GetCenter().Y;
            var dy = ny - y;
            MoveNode(node, y - dy);
        }
        foreach (DiagramLink link in diagram.Links)
        {
            for (int i = 0; i < link.ControlPoints.Count; i++)
            {
                var p = link.ControlPoints[i];
                var dy = p.Y - y;
                p.Y = y - dy;
                link.ControlPoints[i] = p;
            }
            link.UpdateFromPoints(false, false);
        }
        diagram.Invalidate();
    }

    protected void MoveNode(DiagramNode node, float newY)
    {
        var bounds = node.Bounds;
        bounds.Y = newY - bounds.Height / 2;
        node.SetBounds(bounds, false, false);
    }  

Code (C++)

protected void setLinksToSingleSegment(Diagram diagram)
    {
        foreach (DiagramLink link in diagram.Links)
        {
            // If the link is vertical (all X coordinates the same) then reduce the # of segments to 1
            // This will ensure that the Rotate LinkTextStyle and StringAlignment.Center work properly
            // Adapted from code provided by MF

            if (link.SegmentCount == 3 && link.ControlPoints[0].X == link.ControlPoints[1].X && link.ControlPoints[1].X == link.ControlPoints[2].X && link.ControlPoints[2].X == link.ControlPoints[3].X)
            {
	            var p1 = link.ControlPoints[0];
	            var p2 = link.ControlPoints[3];
	            link.Style = LinkStyle.Polyline;
                //link.Shape = LinkShape.Polyline; // NetDiagram V5
	            link.SegmentCount = 1;
	            link.ControlPoints[0] = p1;
	            link.ControlPoints[1] = p2;
	            link.UpdateFromPoints();
            }

            // If the link is horizontal (all Y coordinates the same) then reduce the # of segments to 1
            // This will ensure that the Rotate LinkTextStyle and StringAlignment.Center work properly

            if (link.SegmentCount == 3 && link.ControlPoints[0].Y == link.ControlPoints[1].Y && link.ControlPoints[1].Y == link.ControlPoints[2].Y && link.ControlPoints[2].Y == link.ControlPoints[3].Y)
            {
                var p1 = link.ControlPoints[0];
                var p2 = link.ControlPoints[3];
                link.Style = LinkStyle.Polyline;
                //link.Shape = LinkShape.Polyline; // NetDiagram V5
                link.SegmentCount = 1;
                link.ControlPoints[0] = p1;
                link.ControlPoints[1] = p2;
                link.UpdateFromPoints();
            }
        }
    } 

Code (C++)

protected void fixSelfLoopBackLinks(Diagram diagram)
    {
        foreach (DiagramLink link in diagram.Links)
        {
            if (link.Origin == link.Destination)  // Is this a loop back to the same state?
            {
                RectangleF r = link.Origin.Bounds;
                float centerx = r.Left + r.Width / 2;
                float dist = 16;
                SetLinkPoints(link,
                    new PointF(centerx, r.Top),
                    new PointF(centerx - dist, r.Top - dist),
                    new PointF(centerx + dist, r.Top - dist),
                    new PointF(centerx, r.Top));
            }
        }
    }