FarPoint.Win.Chart.PieSeries series = new FarPoint.Win.Chart.PieSeries();

        private void Form1_Load(object sender, EventArgs e)
        {                       
            series.SeriesName = "Series 1";
            series.TopBevel = new FarPoint.Win.Chart.CircleBevel(12.0f, 12.0f);
            series.BottomBevel = new FarPoint.Win.Chart.CircleBevel(12.0f, 12.0f);
            series.Values.Add(1.0);
            series.Values.Add(2.0);
            series.Values.Add(4.0);
            series.Values.Add(8.0);

            FarPoint.Win.Chart.PiePlotArea plotArea = new FarPoint.Win.Chart.PiePlotArea();
            plotArea.Location = new PointF(0.2f, 0.2f);
            plotArea.Size = new SizeF(0.6f, 0.6f);
            plotArea.series.Add(series);

           
            FarPoint.Win.Chart.ChartModel model = new FarPoint.Win.Chart.ChartModel();
            model.PlotAreas.Add(plotArea);
            fpChart1.Model = model;            
        }

private void button1_Click(object sender, EventArgs e)
        {
    series.Values.Clear();        
         }

private void button2_Click(object sender, EventArgs e)
        {
    series.Values[3] = 1;
         }

private void button3_Click(object sender, EventArgs e)
        {
    double v;
    v = series.Values[3];
    textBox1.Text = v.ToString();
         }