private void button2_Click(object sender, EventArgs e) {
DataTable dtCloned = csvData.Clone();
dtCloned.Columns["column name"].DataType = typeof(double);
dtCloned.Columns["column name"].DataType = typeof(double);
chart1.DataSource = dtCloned;
chart1.ChartAreas[0].AxisX.Minimum = 0;
chart1.ChartAreas[0].AxisX.Maximum = 10;
chart1.ChartAreas[0].AxisX.Minimum = -5;
chart1.ChartAreas[0].AxisX.Maximum = 5;
chart1.Series["Series2"].YValueMembers = "Delta_Sigma";
chart1.Series["Series2"].XValueMember = "CpK_Refrence";
chart1.DataBind();
}