图表不显示在Web表单上

Question

我在网络表单上的图表有问题。 我点击一个按钮显示图表时出现“undefined”错误。我的代码背后是... 我的图表显示在网络表单上有问题。 我点击一个按钮显示图表时出现“undefined”的错误。下面是我的代码...

public partial class Dashboard : System.Web.UI.Page
{
    public ActionResult Index()
    {
        return View();
    }

    private ActionResult View()
    {
        return View();
    }

    // Using ADO.NET Code
    public JsonResult ChartFunction()
    {
        string query = "select [Month],SalesCount from ProductSales";
        string constring = @"Data Source=JOHN-PC;Initial Catalog=SmartCare_Melchizedek ;Integrated Security=True;";
        List<ProductDetails> chartData = new List<ProductDetails>();
        using (SqlConnection con = new SqlConnection(constring))
        {
            using (SqlCommand cmd = new SqlCommand(query))
            {
                cmd.CommandType = CommandType.Text;
                cmd.Connection = con;
                con.Open();
                using (SqlDataReader dr = cmd.ExecuteReader())
                {
                    while (dr.Read())
                    {
                        ProductDetails pd = new ProductDetails();
                        pd.Month = dr["Month"].ToString();
                        pd.SalesCount = Convert.ToInt32(dr["SalesCount"]);
                        chartData.Add(pd);
                    }
                }
                con.Close();
            }
        }
        return Json(chartData, JsonRequestBehavior.AllowGet);
    }

    private JsonResult Json(List<ProductDetails> chartData, object allowGet)
    {
        return Json(chartData, JsonRequestBehavior.AllowGet);
    }

    class ProductDetails
    {
        public string Month { get; set; }
        public Nullable<int> SalesCount { get; set; }
    }

    public class JsonRequestBehavior
    {
        public static object AllowGet { get; set; }
    }
}