var ds = new HighLowOpenCloseSeries() { Label = "s1" };
  ds.SymbolStrokeThickness = 3; ds.SymbolSize = new Size(20, 20);
  ds.XValuesSource = new DateTime[] {
  new DateTime(2008,10,1), new DateTime(2008,10,2), new DateTime(2008,10,3),
  new DateTime(2008,10,6), new DateTime(2008,10,7), new DateTime(2008,10,8)
  };

  ds.OpenValuesSource = new double[] { 100, 102, 104, 100, 107, 102 };
  ds.CloseValuesSource = new double[] { 102, 104, 100, 107, 102, 100 };
  ds.HighValuesSource = new double[] { 102, 105, 105, 108, 109, 105 };
  ds.LowValuesSource = new double[] { 99, 95, 95, 100, 96, 99, 98 };
  ds.PlotElementLoaded += new EventHandler(ds_PlotElementLoaded);
  c1Chart1.Data.Children.Add(ds);
  c1Chart1.ChartType = ChartType.Candle;
  }

void ds_PlotElementLoaded(object sender, EventArgs e)
  {
    var pe = (PlotElement)sender;
    // main canvas
    var cnv = pe.Parent as Canvas;
   // get data coordinates
   var x = (DateTime)pe.DataPoint["XValues"]; 
   var high = (double)pe.DataPoint["HighValues"];
   var low = (double)pe.DataPoint["LowValues"];
   // convert to pixel coordinates
   var pthigh = c1Chart1.View.PointFromData(new Point(x.ToOADate(), high));
   var ptlow = c1Chart1.View.PointFromData(new Point(x.ToOADate(), low));
  // add labels
  cnv.Children.Add(CreateLabel(pthigh, high.ToString()));
  cnv.Children.Add(CreateLabel(ptlow, low.ToString()));
  }

TextBlock CreateLabel(Point pt, string text)
  {
   var tb = new TextBlock() { Text = text };
   Canvas.SetLeft(tb, pt.X); Canvas.SetTop(tb, pt.Y);
   return tb;
  }