AngularJsCascardingDropdownlist.cs

//Method to populate the Initial Dropdownlist
        [System.Web.Services.WebMethod()]
        public static List<OrderList> GetProductList()
        {
            List<OrderList> list = new List<OrderList>();
            using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NORTHWINDConnectionString"].ConnectionString))
            {
                conn.Open();
                string strquery = "Select TOP 10 * from Orders";
                using (SqlCommand cmd = new SqlCommand(strquery, conn))
                {
                    SqlDataReader reader = cmd.ExecuteReader();
                    while (reader.Read())
                    {
                        OrderList objorder = new OrderList(int.Parse(reader["OrderID"].ToString()), reader["ShipAddress"].ToString(), reader["ShipName"].ToString(), double.Parse(reader["Freight"].ToString()));
                        list.Add(objorder);
                    }
                }
 
            }
            return list;
        }
 
        [System.Web.Services.WebMethod()]
        public static List<CustomerList> GetCustomerList(int orderID)
        {
            List<CustomerList> list = new List<CustomerList>();
            using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NORTHWINDConnectionString"].ConnectionString))
            {
                conn.Open();
                string strquery = "Select CustomerID from Orders where OrderID = @orderID";
                using (SqlCommand cmd = new SqlCommand(strquery, conn))
                {
                    cmd.Parameters.AddWithValue("@orderID", orderID);
                    SqlDataReader reader = cmd.ExecuteReader();
                    while (reader.Read())
                    {
                        CustomerList objorder = new CustomerList(reader["CustomerID"].ToString());
                        list.Add(objorder);
                    }
                }
 
            }
            return list;
        }
 
        public class CustomerList
        {
            public string CustomerName;
            public CustomerList(string customerName)
            {
                CustomerName = customerName;
            }
        }
 
        public class OrderList
        {
            public int OrderID;
            public string ShipName;
            public string ShipAddress;
            public double Freight;
            public OrderList(int orderID, string shipName, string shipAddress, double freight)
            {
                OrderID = orderID;
                ShipName = shipName;
                ShipAddress = shipAddress;
                Freight = freight;
            }
        }