笔记：DropDownList无限级分类(灵活控制显示形式)

主要使用递归实现，数据库结构：

最终样式：

 1 protected   void  Page_Load( object  sender, EventArgs e)
 2      {
 3        if (!Page.IsPostBack)
 4        {
 5            BindDrpClass();
 6        }
 7    }
 8      // 绑定顶级分类
 9      private   void  BindDrpClass()
10      {
11        Bll.Class classSystem = new Bll.Class();
12        DataTable dt = classSystem.GetClassList("").Tables[0];
13        ddlClass.Items.Clear();
14        ddlClass.Items.Add(new ListItem("添加根栏目","0"));
15        DataRow[] drs = dt.Select("ParentID= " + 0);
16
17        foreach (DataRow dr in drs)
18        {
19            string classid = dr["ClassID"].ToString();
20            string classname = dr["ClassName"].ToString();
21            //顶级分类显示形式
22            classname = "╋" + classname;
23
24            ddlClass.Items.Add(new ListItem(classname, classid));
25            int sonparentid = int.Parse(classid);
26            string blank = "├";
27            //递归子分类方法
28            BindNode(sonparentid, dt, blank);
29        }
30        ddlClass.DataBind();
31    }
32      // 绑定子分类
33      private   void  BindNode( int  parentid, DataTable dt,  string  blank)
34      {
35        DataRow[] drs = dt.Select("ParentID= " + parentid);
36
37        foreach (DataRow dr in drs)
38        {
39            string classid = dr["ClassID"].ToString();
40            string classname = dr["ClassName"].ToString();
41
42            classname = blank + classname;
43            ddlClass.Items.Add(new ListItem(classname, classid));
44
45            int sonparentid = int.Parse(classid);
46            string blank2 = blank + "─";
47
48            BindNode(sonparentid, dt, blank2);
49        }
50    }

源码下载：

http://files.cnblogs.com/chensubo/RecursionDemo.rar

 

改造过的函数 

// <asp:DropDownList ID="editparentid"  runat="server" ></asp:DropDownList>

   ///   <summary>
     ///   加载页面 
     /// </summary>
     protected   void  Page_Load( object  sender, EventArgs e)
    {

       BindDrpClass(editparentid);}

/// <summary>

///  创建树
     ///   </summary>
     public   void  BindDrpClass(DropDownList ddlClass)
    {
        DataTable dt  =  DbHelper.ExecuteDataset(SysConst.DBNAME_XIAOWU,  " select * from NT_Clcs_ClientType " ).Tables[ 0 ];
        ddlClass.Items.Clear();
        ddlClass.Items.Add( new  ListItem( " 添加根栏目 " ,  " 0 " ));
        DataRow[] drs  =  dt.Select( " ParentID=  "   +   0 );
         foreach  (DataRow dr  in  drs){
             string  classid  =  dr[ " Cc_ID " ].ToString();
             string  classname  =  dr[ " Cc_Name " ].ToString();
             // 顶级分类显示形式
            classname  =   " ╋ "   +  classname;

            ddlClass.Items.Add( new  ListItem(classname, classid));
             int  sonparentid  =   int .Parse(classid);
             string  blank  =   " ├ " ;
             // 递归子分类方法
            BindNode(ddlClass, sonparentid, dt, blank);
        }
        editparentid.DataBind();
    }
     ///   <summary>
     ///  创建树结点
     ///   </summary>
     private   void  BindNode(DropDownList ddlNode,  int  parentid, DataTable dt,  string  blank)
    { 
        DataRow[] drs  =  dt.Select( " ParentID=  "   +  parentid);
         foreach  (DataRow dr  in  drs){
             string  classid  =  dr[ " Cc_ID " ].ToString();
             string  classname  =  dr[ " Cc_Name " ].ToString();
            classname  =  blank  +  classname;
            ddlNode.Items.Add( new  ListItem(classname, classid));
             int  sonparentid  =   int .Parse(classid);
             string  blank2  =  blank  +   " ─ " ;
            BindNode(ddlNode,sonparentid, dt, blank2);
        }
    }

 

二次改造做成一个通用的类 调用  如：  new DrpGradingList("select * from dbo.NT_Clcs_ClientType ", "Cc_Name", "Cc_ID", defValue).BindDrpClass(ddl);

 

     ///   <summary>
     ///  DropDownList 树形显示
     ///   </summary>
     public  class DrpGradingList
    {
         private  string Sql =  "";
         private  string Text =  "";
         private  string Value =  "";
         private  string defValue =  "";
         private  string parentId =  " ParentID ";
         ///   <summary>
         ///   DropDownList 树形显示
         ///   </summary>
         ///   <param name="sql"> SQL语句 </param>
         ///   <param name="text"> 显示的文本（ 数据库字段） </param>
         ///   <param name="value"> 显示的文本对应的值（ 数据库字段） </param>
         public DrpGradingList( string sql,  string text,  string value,  string defvalue)
        {
             this.Sql = sql;
             this.Text = text;
             this.Value = value;
             this.defValue = defvalue;
        }
         ///   <summary>
         ///   DropDownList 树形显示
         ///   </summary>
         ///   <param name="sql"> SQL语句 </param>
         ///   <param name="text"> 显示的文本（ 数据库字段） </param>
         ///   <param name="value"> 显示的文本对应的值（ 数据库字段） </param>
         public DrpGradingList( string sql,  string text,  string value,  string defvalue, string pid)
        {
             this.Sql = sql;
             this.Text = text;
             this.Value = value;
             this.defValue = defvalue;
             this.parentId = pid;
        }
         ///   <summary>
         ///  创建树
         ///   </summary>
         public  void BindDrpClass(DropDownList ddlClass)
        {
            DataTable dt = DbHelper.ExecuteDataset(SysConst.DBNAME_XIAOWU, Sql).Tables[ 0];
            ddlClass.Items.Clear();
            ddlClass.Items.Add( new ListItem( " 顶级栏目 ",  " 0 "));
            DataRow[] drs = dt.Select( ""+ this.parentId+ " =  " +  0);
             foreach (DataRow dr  in drs)
            {
                 string classid = dr[ this.Value].ToString();
                 string classname = dr[ this.Text].ToString();
                 // 顶级分类显示形式
                classname =  " ╋ " + classname;

                ListItem itme =  new ListItem();
                itme.Text=classname;
                itme.Value=classid;
                 if (itme.Value.Equals( this.defValue))
                    itme.Selected =  true;

                ddlClass.Items.Add(itme);
                 int sonparentid =  int.Parse(classid);
                 string blank =  " ├ ";
                 // 递归子分类方法
                BindNode(ddlClass, sonparentid, dt, blank);
            }
            ddlClass.SelectedIndex = ddlClass.Items.IndexOf(ddlClass.Items.FindByValue( this.defValue));
            ddlClass.DataBind();
        }
         ///   <summary>
         ///  创建树  ddlClass.Items.Add(new ListItem("顶级栏目", "0"));
         ///   </summary>
         public  void BindDrpClass(DropDownList ddlClass,  bool defItem)
        {
            DataTable dt = DbHelper.ExecuteDataset(SysConst.DBNAME_XIAOWU, Sql).Tables[ 0];
            ddlClass.Items.Clear();
             if (defItem){
                ddlClass.Items.Add( new ListItem( " 顶级栏目 ",  " 0 "));
            }
            DataRow[] drs = dt.Select( "" +  this.parentId +  " =  " +  0);
             foreach (DataRow dr  in drs)
            {
                 string classid = dr[ this.Value].ToString();
                 string classname = dr[ this.Text].ToString();
                 // 顶级分类显示形式
                classname =  " ╋ " + classname;

                ListItem itme =  new ListItem();
                itme.Text = classname;
                itme.Value = classid;
                 if (itme.Value.Equals( this.defValue))
                    itme.Selected =  true;

                ddlClass.Items.Add(itme);
                 int sonparentid =  int.Parse(classid);
                 string blank =  " ├ ";
                 // 递归子分类方法
                BindNode(ddlClass, sonparentid, dt, blank);
            }
            ddlClass.SelectedIndex = ddlClass.Items.IndexOf(ddlClass.Items.FindByValue( this.defValue));
            ddlClass.DataBind();
        }
         public  void BindDrpClass(DropDownList ddlClass,  bool defItem, string parentIdefVale)
        {
             if (parentIdefVale.Length ==  0) parentIdefVale =  " 0 ";
            DataTable dt = DbHelper.ExecuteDataset(SysConst.DBNAME_XIAOWU, Sql).Tables[ 0];
            ddlClass.Items.Clear();
             if (defItem)
            {
                ddlClass.Items.Add( new ListItem( " 顶级栏目 ",  " 0 "));
            }
            DataRow[] drs = dt.Select( "" +  this.parentId +  " =  " + parentIdefVale);
             foreach (DataRow dr  in drs)
            {
                 string classid = dr[ this.Value].ToString();
                 string classname = dr[ this.Text].ToString();
                 // 顶级分类显示形式
                classname =  " ╋ " + classname;

                ListItem itme =  new ListItem();
                itme.Text = classname;
                itme.Value = classid;
                 if (itme.Value.Equals( this.defValue))
                    itme.Selected =  true;

                ddlClass.Items.Add(itme);
                 int sonparentid =  int.Parse(classid);
                 string blank =  " ├ ";
                 // 递归子分类方法
                BindNode(ddlClass, sonparentid, dt, blank);
            }
            ddlClass.SelectedIndex = ddlClass.Items.IndexOf(ddlClass.Items.FindByValue( this.defValue));
            ddlClass.DataBind();
        }
         ///   <summary>
         ///  创建树结点
         ///   </summary>
         private  void BindNode(DropDownList ddlNode,  int parentid, DataTable dt,  string blank)
        {
            DataRow[] drs = dt.Select( ""+ this.parentId+ " =  " + parentid);
             foreach (DataRow dr  in drs)
            {
                 string classid = dr[ this.Value].ToString();
                 string classname = dr[ this.Text].ToString();
                classname = blank + classname;

                ListItem itme =  new ListItem();
                itme.Text = classname;
                itme.Value = classid;
                 if (itme.Value.Equals( this.defValue))
                    itme.Selected =  true;
                ddlNode.Items.Add(itme);

                 int sonparentid =  int.Parse(classid);
                 string blank2 = blank +  " ─ ";
                BindNode(ddlNode, sonparentid, dt, blank2);
            }
        }
    }

 

 RadTreeView控件 应用：

 

 

< telerik:RadTreeView  runat ="server"  ID ="RadTreeView2"  Skin ="Office2007"
             Width ="300px"  Height ="450px"  CheckBoxes ="True"  DataTextField ="ParentID"  
                TriStateCheckBoxes ="False" >
             </ telerik:RadTreeView >   

 

 AddTree( " 0 " ,  this .RadTreeView2.Nodes);

  public   void  AddTree( string  fdm, RadTreeNodeCollection nodes)
    {
        DataTable dt  =  DbHelper.ExecuteDataset(SysConst.DBNAME_XIAOWU,  " select * from NT_Clcs_Village where ParentID= "   +  fdm  +   "" ).Tables[ 0 ];

         foreach  (DataRow dr  in  dt.Rows)
        {
             string  classid  =  dr[ " Cv_ID " ].ToString();
             string  classname  =  dr[ " Cv_Name " ].ToString();

            RadTreeNode main  =   new  RadTreeNode();
            main.Text  =  classname;
            main.Value  =  classid;
            nodes.Add(main);
            AddTree(classid, main.Nodes);
        }

   } 

 其它：

dropDownList.SelectedIndex=dropDownList.Items.IndexOf(dropDownList.Items.FindByText(entityBase.Bugstatus));

 MVC树形：

使用： @Html.DropDownList("ddlXzqy", ViewData["ddlXzqy"] as IEnumerable<SelectListItem>) 

 /// <summary>
        /// 创建树
        /// </summary>
        public void BindDrpClass(Guid selectId)
        {
            var list = repo.GetXzqyRootsList();
            List<SelectListItem> selitem = new List<SelectListItem>();
            foreach (var item in list)
            {
                //顶级分类显示形式
                if (selectId == item.ID)
                {
                    selitem.Add(new SelectListItem { Text = "╋" + item.Name, Value = item.ID.ToString(), Selected = true });
                    this.ViewData["selected"] = item.ID.ToString();
                }
                else
                {
                    selitem.Add(new SelectListItem { Text = "╋" + item.Name, Value = item.ID.ToString() });
                }

                //递归子分类方法
                string blank = "├";
                BindNode(item.ID, blank, selitem, selectId);
            }
            selitem.Insert(0, new SelectListItem { Text = "==行政区域==", Value = "-1" });
            ViewData["ddlXzqy"] = selitem;
        }
        private void BindNode(Guid parentid, string blank, List<SelectListItem> selitem, Guid selectId)
        {
            var list = repo.GetXzqyChildList(parentid);
            foreach (var item in list)
            {
                if (selectId == item.ID)
                {
                    selitem.Add(new SelectListItem { Text = blank + item.Name, Value = item.ID.ToString(), Selected = true });
                    this.ViewData["selected"] = item.ID.ToString();
                }
                else
                {
                    selitem.Add(new SelectListItem { Text = blank + item.Name, Value = item.ID.ToString() });
                }
                string blank2 = blank + "─";
                BindNode(item.ID, blank2, selitem, selectId);
            }
        }