通过mvc中的模型绑定编辑强类型下拉列表

Question

在我的模型中声明selectcountrylist，lstcountry和countryname属性..，

public class Student
    {
        public int StudentID { get; set; }

        [Required(ErrorMessage = "StudentName Is Required")]
        public string StudentName { get; set; }

        public int CountryID { get; set; }

        [Required(ErrorMessage = "CountryName Is Required")]
        public string CountryName { get; set; }

        public string ActionName { get; set; }
        public int StateID { get; set; }

        [Required(ErrorMessage = "StateName Is Required")]
        public string StateName { get; set; }

        public int CityID { get; set; }

        [Required(ErrorMessage = "CityName Is Required")]
        public string CityName { get; set; }
        public List<SelectListItem> lstCountry { get; set; }

        public List<SelectListItem> lstState { get; set; }

        public List<Student> StudentList { get; set; }

    }

通过使用引用调用创建对象，属性但在所有字段中选择的值在列表中为零

 public ActionResult Edit(int studentID)
        {
            Student studentobj = new Student();
            using (SqlConnection Con = new SqlConnection(_ConnectionString))
            {
                Con.Open();
                try
                { 
                    SqlCommand cmd = new SqlCommand("EditStudent", Con);
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@StudentID", studentID);
                    SqlDataReader _Reader = cmd.ExecuteReader();
                   while( _Reader.Read())
                    {
                        studentobj.StudentName = _Reader["StudentName"].ToString();
                        studentobj.CountryID = Convert.ToInt32(_Reader["CountryID"]);
                        studentobj.CountryName = _Reader["CountryName"].ToString();
                        studentobj.StateName = _Reader["StateName"].ToString();
                        studentobj.CityName = _Reader["CityName"].ToString();                 
                      studentobj.lstCountry = GetCountry();
                    }
                }
                catch (Exception ex)
                {
                    Con.Close();
                    throw ex;
                }

            }
            return View(studentobj);
        }

在视图中覆盖数据库中的选择值，而不是选择值，它显示列表..，

@Html.DropDownListFor(model => model.CountryName , new SelectList(Model.lstCountry, "Value", "Text"), "select")