[Solved] ASP.Net Chart Error: The name SeriesChartType does not exist in the current context

I followed your article to display pie chart

Populate ASP.Net 4.0 Chart Control Pie Chart from SQL Server Database

it is showing me error on this following line

Chart1.Series[0].ChartType = SeriesChartType.Pie;

Compiler Error Message: CS0103: The name 'SeriesChartType' does not exist in the current context

I am using Visual Studio 2010.

private void BindGrid()
{
    con = new SqlDbConnect();
    con.SqlQuery(@"select 'Dispatch Local' as 'Head',Sum(TotalPrice) 'Amount' from tblDispatchLocal
                   union all
                   select 'Sales Trans:' as 'Head',Sum(P_Price) 'Amount' from tblSalesTran
                    ;");//union all select 'Loan Recovery:' as 'Head',Sum(R_Amount) 'Amount' from tblLoanRefund;
    adapt.SelectCommand = con.Cmd;
    adapt.Fill(sTable);
    if (sTable.Rows.Count > 0)
    {
        GridView1.DataSource = sTable;
        GridView1.DataBind();
 
        GridView1.FooterRow.Cells[0].Text = "Total:";
        GridView1.FooterRow.Cells[0].Font.Bold = true;
        GridView1.FooterRow.Cells[0].HorizontalAlign = HorizontalAlign.Right;
 
        decimal totalDis = sTable.AsEnumerable().Sum(row => row.Field<decimal>("Amount"));
        GridView1.FooterRow.Cells[1].Text = totalDis.ToString();
        GridView1.FooterRow.Cells[1].HorizontalAlign = HorizontalAlign.Center;
        GridView1.FooterRow.Cells[1].Font.Bold = true;
        GridView1.FooterRow.Cells[1].BackColor = System.Drawing.Color.Yellow;
 
        string[] x = new string[sTable.Rows.Count];
        decimal[] y = new decimal[sTable.Rows.Count];
        for (int i = 0; i < sTable.Rows.Count; i++)
        {
            x[i] = sTable.Rows[i][0].ToString();
            y[i] = Convert.ToDecimal(sTable.Rows[i][1].ToString());
        }
        Chart1.Series[0].Points.DataBindXY(x, y);
        Chart1.Series[0].ChartType = SeriesChartType.Pie;
        Chart1.ChartAreas["ChartArea1"].Area3DStyle.Enable3D = true;
        Chart1.Legends[0].Enabled = true;
    }
}

How to fix this issue plz.