ASP.NET

代码：

        //声明泛型
        List<category> inof = new List<category>();//二级分类

        //声明类使用的对象类
        public class category
        {
            public category(string id, string name)
            {
                Id = id;
                Name = name;
            }

            private string id;

            public string Id
            {
                get { return id; }
                set { id = value; }
            }

            private string name;

            public string Name
            {
                get { return name; }
                set { name = value; }
            }
        }

        //获取信息
        public void selectdatabind()
        {
            SqlDataReader sdr = SQLHelper.ExcuteReader("select ID, CategoryName from Tb_APCategory where ParentID = 1000", CommandType.Text);
            while (sdr.Read())
            {
                SqlDataReader sdr_2 = SQLHelper.ExcuteReader("select ID, CategoryName from Tb_APCategory where ParentID = " + sdr["ID"].ToString() + "", CommandType.Text);
                while (sdr_2.Read())
                {
                    inof.Add(new category(sdr_2["ID"].ToString(), sdr_2["CategoryName"].ToString()));
                }
            }
        }


        //使用
        this.DropDownList2.DataSource = inof;
        this.DropDownList2.DataValueField = "ID";
        this.DropDownList2.DataTextField = "Name";
        this.DropDownList2.DataBind();