Code

AnchorPattern ap5;

private void Form1_Load(object sender, System.EventArgs e)
{
  fc.SnapToAnchor = SnapToAnchor.OnCreateOrModify;

  // define five incoming anchor points
  AnchorPointCollection points = new AnchorPointCollection();
  for (short i = 0; i < 5; i++)
  {
    points.Add(new AnchorPoint((short)(10 + i * 20), 0,
     true, false, MarkStyle.Circle, Color.Blue));
  }

  // and one outgoing
  points.Add(new AnchorPoint(50, 100, false, true));

  ap5 = new AnchorPattern(points);
  AnchorPattern.Register(ap5);
}

private void fc_InitializeBox(object sender, MindFusion.Diagramming.WinForms.BoxEventArgs e)
{
  // set the anchor points when users start to draw a new box
  e.Box.AnchorPattern = ap5;
}

private void fc_ValidateAnchorPoint(object sender, MindFusion.Diagramming.WinForms.AttachConfirmArgs e)
{
  // allow at most one arrow to connect to an anchor point
  if (numArrows(e.Node, e.AnchorIndex) > 0)
    e.Confirm = false;
}

private int numArrows(Node node, int anchorIndex)
{
  int total = 0;
  foreach (Arrow arrow in node.IncomingArrows)
    if (arrow.DestAnchor == anchorIndex)
     total++;

  return total;
}