C#实现下拉框绑定list集合的方法

public class Area
{
 //建议编写“实体类”的时候一定要用属性，不要用字段
 //因为有些控件数据绑定的时候只认属性，不认字段（大多数都是）
 public int AreaId
 {
  get;
  set;
 }
 public string AreaName
 {
  get;
  set;
 }
 //public int AreaId;
 //public string AreaName;
 public override string ToString()
 {
  return AreaName;
 }
}

private void LoadProvince()
{
 List<Area> list = new List<Area>();
 #region 初始化List集合
 string constr = ConfigurationManager.ConnectionStrings["sql"].ConnectionString;
 using (SqlConnection con = new SqlConnection(constr))
 {
  string sql = "select * from TblArea where AreaPid=0";
  using (SqlCommand cmd = new SqlCommand(sql, con))
  {
   con.Open();
   using (SqlDataReader reader = cmd.ExecuteReader())
   {
    if (reader.HasRows)
    {
     while (reader.Read())
     {
      //reader的索引是根据实际查询出来的的列的索引来计算的而不是实际表中的索引，除非查询语句使用select *.
      Area model = new Area() { AreaId = reader.GetInt32(0), AreaName = reader.GetString(1) };
      list.Add(model);
     }
    }
   }
  }
 }
 #endregion
 cboProvince.DisplayMember = "AreaName";
 cboProvince.ValueMember = "AreaId";
 cboProvince.DataSource = list;
}