IList<T>实现树形下拉列表

Question

我用sqldatareader 查询出相关信息后，放入IList<实体>中。
我想实现  树形  的下拉列表 请问如何实现（请贴上原代码）不够加分都可以，只有能解决，有源代码。

Answer 1

这个跟IList没啥关系，ILis只是数据源
按规律递归添加
显示文本，下级文本前可以加—

Answer 2

[size=11px][size=10px]
//实体层
 /// <summary>
    /// 实体类Sys_Depart 。(属性说明自动提取数据库字段的描述信息)
    /// </summary>
    [Serializable]
    public class Sys_Depart
    {
        public Sys_Depart()
        { }
        #region Model
        private int _oid;
        private string _deptid;
        private string _deptname;
        private string _shortname;
        private Guid _parentid;
        private string _re;
        /// <summary>
        /// 系统编号(自增）
        /// </summary>
        public int OID
        {
            set { _oid = value; }
            get { return _oid; }
        }
        /// <summary>
        /// 组织机构ID
        /// </summary>
        public string DeptID
        {
            set { _deptid = value; }
            get { return _deptid; }
        }
        /// <summary>
        /// 组织机构名称
        /// </summary>
        public string DeptName
        {
            set { _deptname = value; }
            get { return _deptname; }
        }
        /// <summary>
        /// 组织机构简称
        /// </summary>
        public string ShortName
        {
            set { _shortname = value; }
            get { return _shortname; }
        }
        /// <summary>
        /// 上级ID
        /// </summary>
        public Guid ParentID
        {
            set { _parentid = value; }
            get { return _parentid; }
        }
        /// <summary>
        /// 备注
        /// </summary>
        public string Re
        {
            set { _re = value; }
            get { return _re; }
        }
        #endregion Model    }//数据层的方法
 public IList<Sys_Depart> getlist()
        {
            StringBuilder sb = new StringBuilder();
            sb.Append("SELECT [OID],[DeptID],[DeptName],[ShortName],[ParentID],[Re]");
            sb.Append(" FROM [dbo].[Sys_Depart] ");          
         
            SqlParameter[] PMS = null;
            IList<Sys_Depart> listEntity = new List<Sys_Depart>();
            Sys_Depart Entity= null;
            using (SqlDataReader Dr = (SqlDataReader) this.Session.ExecuteReader(CommandType.Text, sb.ToString(), PMS))
            {
               while (Dr.Read())
                {
                    Entity = new Sys_Depart();
                    if (!ComFun.IsDBNull(Dr["OID"]))//comFun.IsDBNull是自己写的函数，是否为空
                    {
                        Entity.OID =int.Pase(Dr["OID"].ToString());
                    }
                    if (!ComFun.IsDBNull(Dr["DeptID"]))
                    {
                        Entity.DeptID = Dr["DeptID"].ToString();
                    }
                    if (!ComFun.IsDBNull(Dr["DeptName"]))
                    {
                        Entity.DeptName = Dr["DeptName"].ToString();
                    }
                    if (!ComFun.IsDBNull(Dr["ShortName"]))
                    {
                        Entity.ShortName = Dr["ShortName"].ToString();
                    }
                    if (!ComFun.IsDBNull(Dr["ParentID"]))
                    {
                        Entity.ParentID = new Guid(Dr["ParentID"].ToString());
                    }
                    if (!ComFun.IsDBNull(Dr["Re"]))
                    {
                        Entity.Re = Dr["Re"].ToString();
                    }
                    listEntity.Add(Entity);
                     
                }
                if (!Dr.IsClosed)
                    Dr.Close();
            }
            return listEntity;
               
        }
现在我想实现ILIST<实体> 用树形方式的下拉列表显示！！！！！！！！

Answer 3

 protected void Page_Load(object sender, EventArgs e)
        {
            List<int> list = new List<int>();
            list.Add(1);
            list.Add(2);
            list.Add(3);
            list.Add(4);
            list.Add(5);
            DropDownList1.DataSource = list;
            DropDownList1.DataBind();
        }

Answer 4

 protected void Page_Load(object sender, EventArgs e)
        {
            IList<int> list = new List<int>();
            list.Add(1);
            list.Add(2);
            list.Add(3);
            list.Add(4);
            list.Add(5);
            DropDownList1.DataSource = list;
            DropDownList1.DataBind();
        }

Answer 5

额 数据库中都有父类ID了 
你就把父类的ID用ADD添加上 然后子类的文件用递归添加

Answer 6

    private void TreeViewBind() { for (int i = 0; i < List.Count; i++) { if (List[i].ParentID == null) { TreeNode level1Node = new TreeNode(); level1Node.Text = List[i].Name; level1Node.Value = List[i].ID.ToString(); tv.Nodes.Add(level1Node); InitialTree(level1Node, List[i].ID);
                }
            }
        }
//递归的方法
private void InitialTree(TreeNode parentNode, int Id)
        {
            for (int i = 0; i < List.Count; i++)
            {
                if (List[i].ID == parentId)
                {
                    TreeNode childNode = new TreeNode();
                    childNode.Text = List[i].Name;
                    childNode.Value = List[i].ID.ToString();
                   
                    InitialTree(childNode, List[i].ID);
                    parentNode.ChildNodes.Add(childNode);
                }
            }
        }List是查询出的数据 

Answer 7

    public class DDLDepartment : DropDownList
    {
        private bool _blank;        public DDLDepartment()
        {
            bind(this, 0);
            this.Items.Insert(0, new ListItem("==请选择==", ""));
        }        public void bind(DropDownList ddlDepartment, int parent)
        {
            IList<Department> deptlist = DepartmentBLL.SelectChild(parent);
            foreach (Department dept in deptlist)
            {
                string text = new string('　', dept.Depth - 1);
                text += "└" + dept.DeptName;
                ddlDepartment.Items.Add(new ListItem(text, dept.DeptId.ToString()));
                bind(this, dept.DeptNo);
            }
        }        public bool Blank
        {
            set
            {
                _blank = value;
                if (value == false) this.Items.RemoveAt(0);
            }
            get
            {
                return _blank;
            }
        }
    }
Department为实体类