Chart: PixelPositionToValue not accurate when finding x,y coordinates

Question

I am trying to display the X and Y coordinates of the chart data in a small display. Everything works well but the data shown isn't accurate.

Here is the code below:

 var results = chart1.HitTest(e.X, e.Y, false, ChartElementType.PlottingArea);

            foreach (var result in results)
            {
                if (result.ChartElementType == ChartElementType.PlottingArea)
                {
                    yValue = chart1.ChartAreas[0].AxisY2.PixelPositionToValue(e.Y);
                    xValue = chart1.ChartAreas[0].AxisX2.PixelPositionToValue(e.X);
                }
            }
            if (OverlapcheckBox1.Checked)
            {
                int val = Convert.ToInt16(yValue / 24);
                yValue = yValue - 24 * val;

            }
            if (Cursor1checkBox.Checked && ClickMouse)
            {
                V1textBox1.Text = string.Concat(string.Concat(yValue).ToString());
            }
            if (Cursor2checkBox.Checked && ClickMouse)
            {
                V2textBox2.Text = string.Concat(string.Concat(yValue).ToString());
            }

The image shows cursor at 10 but the value in V1 is 9.88 And an image:

Answer 1

Unless your mouse has amazing accuracy you would never see an exact 10.000. You could round it off:

private void Chart1_MouseClick(object sender, MouseEventArgs e) {
    double yValue = chart1.ChartAreas[0].AxisY.PixelPositionToValue(e.Y);
    yValue = Math.Round(yValue, 0);
}

Or perhaps you wish to find DataPoints near the cursor click position?

private void Chart1_MouseClick(object sender, MouseEventArgs e) {

    HitTestResult result = chart1.HitTest(e.X, e.Y);

    if (result.ChartElementType == ChartElementType.DataPoint) {
        DataPoint point = (DataPoint)result.Object;
        double yValue = point.YValues[0];
    }
}