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（无限级、递归）DropDownList显示树形分类

發布時間：2024/4/11 编程问答 35 豆豆

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簡單無限級表結構：id，name，pid。

本篇將展示如何在DropDownList控件顯示一個漂亮的樹結構。

1.以下我們建立無限級樹的表結構

--星辰變的修真等級表
CREATE?TABLE XianMO
(
XianMoID INT?NOT?NULL ,
XianMoLevel VARCHAR(50) NOT?NULL?DEFAULT(''),
XianMoParentID INT?NOT?NULL?DEFAULT(0)
)
GO
--索引
CREATE?NONCLUSTERED?INDEX IX_XianMo ON XianMo(XianMoID)
GO

2.有了表結構，我們將添加一些數據。^_^

INSERT?INTO XianMo(XianMoID,XianMoLevel,XianMoParentID) SELECT?1,'凡人',0
UNION?ALL?SELECT?2,'修真者',0
UNION?ALL?SELECT?3,'后天境界',2
UNION?ALL?SELECT?4,'先天境界(四九小天劫)',2
UNION?ALL?SELECT?5,'金丹期',2
UNION?ALL?SELECT?6,'元嬰期(六九大天劫)',2
UNION?ALL?SELECT?7,'洞虛期',2
UNION?ALL?SELECT?8,'空冥期',2
UNION?ALL?SELECT?9,'渡劫期(九九重劫)',2
UNION?ALL?SELECT?10,'大乘期',2
UNION?ALL?SELECT?11,'仙人',0
UNION?ALL?SELECT?12,'散仙',11
UNION?ALL?SELECT?13,'天仙',11
UNION?ALL?SELECT?14,'金仙',11
UNION?ALL?SELECT?15,'玄仙',11
UNION?ALL?SELECT?16,'仙帝',11
UNION?ALL?SELECT?17,'神人',0
UNION?ALL?SELECT?18,'下級神人',17
UNION?ALL?SELECT?19,'中級神人',17
UNION?ALL?SELECT?20,'上級神人',17
UNION?ALL?SELECT?21,'天神',0
UNION?ALL?SELECT?22,'下部天神',21
UNION?ALL?SELECT?23,'中部天神',21
UNION?ALL?SELECT?24,'上部天神',21
UNION?ALL?SELECT?25,'神王',0
UNION?ALL?SELECT?26,'天尊',0
UNION?ALL?SELECT?27,'鴻蒙',0
GO

3.創建一個存儲過程，我們在這里就已經把樹結構完整的展示出來了。

-- =============================================
-- Author: Star Studio
-- Create date: 2010-09-10
-- Description: Tree In DropDownList
-- =============================================
ALTER?PROCEDURE[dbo].[GetTree]
@tableName?VARCHAR(100),--表名
@idName?VARCHAR(100),--id字段名
@className?VARCHAR(100),--class字段名
@pidName?VARCHAR(100),--父id字段名
@pidValue?INT,--指定此次構造樹的根節點
@idExcepted?INT--此次構造的樹，將排除顯示的節點及其子節點。這在修改節點的父關系時很有用。你不可以指定某節點的老爸是自己或自己的兒子吧。所以這時就要屏蔽掉自己及子節點
AS
BEGIN
SET NOCOUNT ON;
DECLARE?@Level?INT
DECLARE?@strTree?VARCHAR(8000)
DECLARE?@t?TABLE(id INT,class VARCHAR(100), pid INT)
DECLARE?@ttemp?TABLE(id INT,class VARCHAR(100),pid INT,lev INT,codeid VARCHAR(8000))

SET?@Level=0
SET?@strTree='┊┈┈'

INSERT?INTO?@t?EXEC('SELECT '+@idName+' AS id,'+@className+' AS class,'+@pidName+' AS pid FROM '+@tableName+'') 　　--排除的節點有可能是根節點
INSERT?INTO?@ttemp?SELECT id,@strTree+class,pid,@level,right(10000+id,4) FROM@tWHERE pid=@pidValueAND id<>@idExcepted
WHILE?@@rowcount>0--一層層遞歸構造排序字段codeid
BEGIN
SET?@strTree=replace(@strTree,'┈','')
SET?@strTree=@strTree+'┊┈┈'
SET?@level=@level+1

IF(@idExcepted=0)
BEGIN
INSERT?@ttemp?SELECT a.id,@strTree+a.class,a.pid,@level,b.codeid+right(10000+a.id,4) FROM@t a,@ttemp b
WHERE a.pid=b.id AND b.lev=@level-1
END
ELSE
BEGIN 　　　　　　　--排除的節點是某個子節點
INSERT?@ttemp?SELECT a.id,@strTree+a.class,a.pid,@level,b.codeid+right(10000+a.id,4) FROM@t a,@ttemp b
WHERE a.pid=b.id AND b.lev=@level-1AND b.id<>@idExcepted
END
END 　　--只要按codeid排列結果集，就能得到正確完整的樹結構
SELECT a.id,a.pid,b.class,b.lev,b.codeid FROM?@t a,@ttemp b WHERE a.id=b.id ORDERBY b.codeid
END
GO
--事例演示
exec gettree 'XianMo','xianmoid','xianmolevel','xianmoparentid',0,11

演示事例一及其結果集：

--不排除任何一個節點
exec gettree 'XianMo','xianmoid','xianmolevel','xianmoparentid',0,0

演示事例二及其結果集：

--排除仙人節點
exec gettree 'XianMo','xianmoid','xianmolevel','xianmoparentid',0,11

看了以上兩圖，你應該知道，該存儲過程的原理是通過遞歸構造一個排序字段codeid,然后根據codeid排序就得到完整的屬性排列了。

4.接下來只要把數據放入DropDownList，就能顯示一顆漂亮的樹了。

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="DropDownListTree.aspx.cs" Inherits="_Default"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>DropDownList顯示樹結構</title>
<style type="text/css">
#TreeBlock{width:200px;}
#TreeBlock #ddlXianMoTree{background-color:#FFAA2B; }
</style>
</head>
<body>
<form id="form1" runat="server">
<div id="TreeBlock">
<asp:DropDownList ID="ddlXianMoTree" runat="server"></asp:DropDownList>
</div>
</form>
</body>
</html>

//DropDownListTree.aspx.cs
using System;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Data.SqlClient;
using WnetSoft.Common.DBHelper;

publicpartialclass _Default : System.Web.UI.Page
{
protectedvoid Page_Load(object sender, EventArgs e)
{
SqlParameter[] SqlParamList ={
SqlHelper.MakeInParam("@tableName",SqlDbType.VarChar,100,"XianMo"),
SqlHelper.MakeInParam("@idName",SqlDbType.VarChar,100,"XianMoID"),
SqlHelper.MakeInParam("@className",SqlDbType.VarChar,100,"XianMoLevel"),
SqlHelper.MakeInParam("@pidName",SqlDbType.VarChar,100,"XianMoParentID"),
SqlHelper.MakeInParam("@pidValue",SqlDbType.Int,10,0),
SqlHelper.MakeInParam("@idExcepted",SqlDbType.Int,10,0)
};
ddlXianMoTree.DataSource = SqlHelper.ExecuteReader(SqlHelper.connString, CommandType.StoredProcedure, "GetTree", SqlParamList);
ddlXianMoTree.DataTextField ="class";
ddlXianMoTree.DataValueField ="id";
ddlXianMoTree.DataBind();
ddlXianMoTree.Items.Insert(0, new ListItem("--根節點--", "0"));
}
}

有點遺憾是，我傳入XianMoID，XianMoLevel字段，返回的結果是id,class字段。

以上就是本篇內容。?

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