Hi,

Can anyone recommend a good way to display the current position of a cursor? I can get the value easily enough, but would like to display it as a floating number near the axis that follows the cursor

Is this something that's possible?

Many thanks,
Neil

Hi Neil,

You can achieve this by using the custom values labels - the following code snippets shows a simple point with two dynamic cursors that display the current cursor value at its respective axis:

  private void Form1_Load(object sender, EventArgs e)
  {
   NCartesianChart chart = (NCartesianChart)nChartControl1.Charts[0];
   chart.Dock = DockStyle.Fill;
   chart.BoundsMode = BoundsMode.Stretch;
   chart.MinDockZoneMargins = new NMarginsL(45, 0, 0, 30);

   // sample data
   double[] pointYValues = new double[] { 10, 20, 30 };
   double[] pointXValues = new double[] { 10, 20, 30 };

   NPointSeries point = new NPointSeries();
   point.UseXValues = true;
   chart.Series.Add(point);

   for (int i = 0; i < pointYValues.Length; i++)
   {
    point.Values.Add(pointYValues[i]);
    point.XValues.Add(pointXValues[i]);
   } 

   NAxisCursor cursor1 = new NAxisCursor();
   cursor1.BeginEndAxis = (int)StandardAxis.PrimaryY;
   cursor1.SynchronizeOnMouseAction = MouseAction.Move;
   cursor1.ValueSnapper = new NAxisRulerClampSnapper();
   cursor1.ValueChanged += new EventHandler(cursor1_ValueChanged);
   chart.Axis(StandardAxis.PrimaryX).Cursors.Add(cursor1);

   NAxisCursor cursor2 = new NAxisCursor();
   cursor2.BeginEndAxis = (int)StandardAxis.PrimaryX;
   cursor2.SynchronizeOnMouseAction = MouseAction.Move;
   cursor2.ValueSnapper = new NAxisRulerClampSnapper();
   cursor2.ValueChanged += new EventHandler(cursor2_ValueChanged);
   chart.Axis(StandardAxis.PrimaryY).Cursors.Add(cursor2);

   nChartControl1.Controller.Tools.Add(new NSelectorTool());
   nChartControl1.Controller.Tools.Add(new NDataCursorTool());
  }

  void cursor1_ValueChanged(object sender, EventArgs e)
  {
   NCartesianChart chart = (NCartesianChart)nChartControl1.Charts[0];

   NStandardScaleConfigurator scale = chart.Axis(StandardAxis.PrimaryX).ScaleConfigurator as NStandardScaleConfigurator;
   scale.CustomLabels.Clear();

   NCustomValueLabel label = new NCustomValueLabel();
   label.Value = ((NAxisCursor)sender).Value;
   label.Text = label.Value.ToString("N2");
   scale.CustomLabels.Add(label);

   nChartControl1.Refresh();
  }

  void cursor2_ValueChanged(object sender, EventArgs e)
  {
   NCartesianChart chart = (NCartesianChart)nChartControl1.Charts[0];

   NStandardScaleConfigurator scale = chart.Axis(StandardAxis.PrimaryY).ScaleConfigurator as NStandardScaleConfigurator;
   scale.CustomLabels.Clear();

   NCustomValueLabel label = new NCustomValueLabel();
   label.Value = ((NAxisCursor)sender).Value;
   label.Text = label.Value.ToString("N2");
   scale.CustomLabels.Add(label);

   nChartControl1.Refresh();
  }

Note that the left and bottom axis zones have fixed min width:

chart.MinDockZoneMargins = new NMarginsL(45, 0, 0, 30);

this is done to prevent the chart from bouncing off the edges when the cursor values change.

Hope this helps - let us know if you have any questions...

Best Regards,
Nevron Support Team

Guys,

Is it possible to achieve the same without drawing the crosshair added by the NDataCursorTool?

Thanks,
Plamen

Hi Plamen,

Yes - in this case you have to implement the following steps:

1. Intercept the mouse move event fired by the control.

2. Transform the passed view coordinates to scale coordinates.

The following code snippet shows how to achieve this:

  private void Form1_Load(object sender, EventArgs e)
  {
   NCartesianChart chart = (NCartesianChart)nChartControl1.Charts[0];
   chart.MinDockZoneMargins = new NMarginsL(45, 0, 0, 0);

   NBarSeries bar = new NBarSeries();

   bar.Values.Add(10);
   bar.Values.Add(20);
   bar.Values.Add(30);

   chart.Series.Add(bar);

   nChartControl1.MouseMove += new MouseEventHandler(nChartControl1_MouseMove);
  }

  void nChartControl1_MouseMove(object sender, MouseEventArgs e)
  {
   NHitTestResult result = nChartControl1.HitTest(e.X, e.Y);

   if (result.Chart != null)
   {
    NCartesianChart chart = (NCartesianChart)result.Chart;

    NStandardScaleConfigurator scale = chart.Axis(StandardAxis.PrimaryY).ScaleConfigurator as NStandardScaleConfigurator;
    scale.CustomLabels.Clear();

    NViewToScale2DTransformation transform = new NViewToScale2DTransformation(nChartControl1.View.Context, chart, (int)StandardAxis.PrimaryX, (int)StandardAxis.PrimaryY);
    NPointF point = new NPointF(e.X, e.Y);

    NVector2DD pointScale = new NVector2DD();

    transform.Transform(point, ref pointScale);

    NCustomValueLabel label = new NCustomValueLabel();
    label.Value = pointScale.Y;
    label.Text = label.Value.ToString("N2");
    scale.CustomLabels.Add(label);

    nChartControl1.Refresh();
   }
  }

Hope this helps - let us know if you meet any problems or have any questions.

Best Regards,
Nevron Support Team

I think I've figured it out - I looks like that the code below cures the issue.

NAxisCursor cursor = new NAxisCursor();
cursor.StrokeStyle = new NStrokeStyle(0);