asp/asp.net中遍历树型结构,,CIO之家

asp/asp.net中遍历树型结构

jiny-z　　http://jiny-z.cnblogs.com/　　综合　　编辑:dezai　　图片来源:网络

数据库：SqlServer2000表：tree表结构：

数据库：SqlServer2000
表：tree
表结构：

算法：使用递归实现

======================================
asp代码：

<%@ Language = VBScript%>
<%Option Explicit%>
<%
Dim oConn, sSql
Call DBConnBegin()

Dim sTableName
Dim nCurrent, nLen, aTree()
sTableName = "tree"
nCurrent = 1
nLen = GetRescordCount()

ReDim aTree(nLen)

Call GetPowerName(0)
'Dim i
'For i = 1 To nLen
'Response.Write aTree(i) & "
"
'Next
Call DBConnEnd()

Function GetRescordCount()
GetRescordCount = oConn.Execute("select count(id) from " & sTableName)(0)
End Function

Sub GetPowerName(s_Id)
    Dim n_ParentId, j, oRs
    Set oRs = Server.CreateObject( "ADODB.Recordset" )
    sSql = "select id,PowerName,Layer from " & sTableName & " where ParentId=" & s_Id
    oRs.Open sSql, oConn, 0, 1
    Do While Not oRs.Eof
        For j = 1 To oRs("Layer")
            response.write "    "
        Next
        aTree(nCurrent) = oRs("PowerName")
        response.write aTree(nCurrent) & "
"
        nCurrent = nCurrent + 1
        n_ParentId = oRs("id")
        Call GetPowerName(n_ParentId)
        oRs.MoveNext
    Loop
    oRs.Close
    Set oRs = Nothing
End Sub

Sub DBConnBegin()
' 如果数据库对象已打开，不要再打开
If IsObject(oConn) = True Then Exit Sub

    ' 你可以不需要打开数据库连接对象而直接打开记录集对象，但如果你需要打开多个记录集对象的话，效率是很低的。
    ' 如果你不创建一个数据库连接对象，ADO会在每个记录集打开时自动创建一个新的数据库连接对象，就算你用的是相同的SQL语句。
    Set oConn = Server.CreateObject("ADODB.Connection")

On Error Resume Next

    'Provider=SQLOLEDB.1;Server=(local);Initial Catalog =cx_soft;Integrated Security=SSPI;
    'Provider=SQLOLEDB.1;Server=(local);Initial Catalog =cx_soft;Trusted_Connection=yes;
    oConn.Open "Provider=sqloledb.1;Data Source=(local);Initial Catalog=AspNetTest;User Id=sa;Password=;"

    If Err.Number > 0 Then
        ' 完全地退出正在运行的脚本
        Response.End
    End If

' 创建一个记录集

End Sub

Sub DBConnEnd()
    On Error Resume Next
    oRs.Close
    Set oRs = Nothing
    oConn.Close
    Set oConn = Nothing
End Sub
%>

asp.net代码：
(请注意：asp.net1.1中用同一个Connection，在前一个DataReader没有Close情况下再创建DataReader会出现错误提示：已有打开的与此连接相关联的 DataReader，必须首先将它关闭
我的做法是每次都创建一个Connection，很浪费资源，不知道有没其他好办法.
)
1using System;
2using System.Collections;
3using System.ComponentModel;
4using System.Data;
5using System.Drawing;
6using System.Web;
7using System.Web.SessionState;
8using System.Web.UI;
9using System.Web.UI.WebControls;
10using System.Web.UI.HtmlControls;
11using System.Data.SqlClient;
12
13namespace AspNetTest.Common
14{
15 /**////

16 /// tree 的摘要说明。
17 ///

18
19    public class tree : System.Web.UI.Page
20    {
21        private string tablename = "tree";
22        int current = 0;
23        int len = 0;
24        string[] arrPowerName;
25        string ConnectionString;
26        public tree()
27        {
28            ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"];
29            len = GetRecordCount();
30            arrPowerName = new string[len];
31        }
32        private void Page_Load(object sender, System.EventArgs e)
33        {
34
35            GetPowerName(0);
36            //CloseDbConnection();
37            //ResponseArray();
38            // 在此处放置用户代码以初始化页面
39        }
40        private void GetPowerName(int _ParentId)
41        {
42            int Id;
43            string PowerName;
44            string sql = "select Id,PowerName,Layer from " + tablename + " where ParentId=" + _ParentId;
45            try
46            {
47                SqlConnection conn = new SqlConnection(ConnectionString);
48                conn.Open();
49                SqlCommand cmd = new SqlCommand(sql, conn);
50                SqlDataReader dr = cmd.ExecuteReader();
51                while(dr.Read())
52                {
53                    for(int j=0; j 54                    {
55                        Response.Write("    ");
56                    }
57                    PowerName = dr["PowerName"].ToString();
58                    Response.Write(PowerName + "
");
59                    arrPowerName[current++] = PowerName;
60                    Id = int.Parse(dr["Id"].ToString());
61                    GetPowerName(Id);
62                }
63                dr.Close();
64                conn.Close();
65            }
66            catch(Exception ex)
67            {
68                Response.Write(ex.ToString());
69            }
70        }
71        private void ResponseArray()
72        {
73            int i;
74            for(i=0; i 75            {
76                Response.Write(arrPowerName[i] + "
");
77            }
78        }
79        private void CloseDbConnection()
80        {
81            //conn.Close();
82        }
83        private int GetRecordCount()
84        {
85            SqlConnection conn = new SqlConnection(ConnectionString);
86            string sql = "select count(id) from " + tablename;
87            conn.Open();
88            SqlCommand cmd = new SqlCommand(sql, conn);
89            int count = int.Parse(cmd.ExecuteScalar().ToString());
90            conn.Close();
91            return count;
92        }
93
94        Web 窗体设计器生成的代码#region Web 窗体设计器生成的代码
95        override protected void OnInit(EventArgs e)
96        {
97            //
98            // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
99            //
100            InitializeComponent();
101            base.OnInit(e);
102        }
103
104        /**////

105        /// 设计器支持所需的方法 - 不要使用代码编辑器修改
106        /// 此方法的内容。
107        ///

108        private void InitializeComponent()
109        {
110            this.Load += new System.EventHandler(this.Page_Load);
111
112        }
113        #endregion
114    }
115}
116

遍历结果：

代码下载：

asp代码：/Files/jiny-z/tree(asp).rar
asp.net代码:/Files/jiny-z/tree(asp.net).rar

*********************************************************
根据chill ,flower.b的提示，修改了代码。
原来：asp/asp.net代码中都是在数据集中循环，效率较低.。
现在：asp代码改为在数组中循环，asp.net代码改为在DataTable中循环。
*********************************************************

asp代码：
<%@ Language = VBScript%>
<%Option Explicit%>
<%
Dim oConn, oRs, sSql
Dim aTree
Call FillArrayFromRs()
Call blTreeArray(0)

Sub FillArrayFromRs()
    Dim s_TableName
    s_TableName = "tree"
    Call DBConnBegin()
    Set oRs = Server.CreateObject( "ADODB.Recordset" )
    sSql = "select Id,PowerName,Layer,ParentId from " & s_TableName
    oRs.Open sSql, oConn, 0, 1
    aTree = oRs.GetRows()
    'response.write ubound(aTree, 2)
    oRs.Close
    Call DBConnEnd()
End Sub

Sub blTreeArray(n_ParentId)
    Dim row, rows
    Dim n_NextParentId
    Dim n_Space
    rows = UBound(aTree, 2)
    for row = 0 To rows
        If aTree(3, row) = n_ParentId Then
            for n_Space = 1 To aTree(2, row)
                Response.Write "    "
            Next
            Response.Write aTree(1, row) & "
"
            n_NextParentId = aTree(0, row)
            blTreeArray(n_NextParentId)
        End If
    Next
End Sub

Sub DBConnBegin()
' 如果数据库对象已打开，不要再打开
If IsObject(oConn) = True Then Exit Sub

On Error Resume Next

' 创建一个记录集

End Sub

Sub DBConnEnd()
    On Error Resume Next
    oRs.Close
    Set oRs = Nothing
    oConn.Close
    Set oConn = Nothing
End Sub

%>
asp.net代码：

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace AspNetTest.Common
{
/**////

/// tree_DataTable 的摘要说明。
///

    public class tree_DataTable : System.Web.UI.Page
    {
        private DataTable dtPowerTree = new DataTable();
        const string tablename = "tree";
        private void Page_Load(object sender, System.EventArgs e)
        {
            FillTreeDataTable();
            blTreeDataTable(0);
            dtPowerTree.Clear();
            // 在此处放置用户代码以初始化页面
        }
        private void FillTreeDataTable()
        {
            string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"];
            SqlConnection conn = new SqlConnection(ConnectionString);
            SqlDataAdapter da = new SqlDataAdapter("select Id,PowerName,Layer,ParentId from " + tablename, conn);
            da.Fill(dtPowerTree);
        }
        private void blTreeDataTable(int _ParentId)
        {
            string filter = "ParentId=" + _ParentId;
            string sort = "Id ASC";
            DataRow[] drs = dtPowerTree.Select(filter, sort);
            for(int i=0; i            {
                if(Convert.ToInt32(drs[i][3]) == _ParentId)
                {
                    int Id = Convert.ToInt32(drs[i][0]);
                    string PowerName = drs[i][1].ToString();
                    int Layer = Convert.ToInt32(drs[i][2]);
                    for(int space=1; space<=Layer; space++)
                    {
                        Page.Response.Write("    ");
                    }
                    Page.Response.Write(PowerName + "
");
                    blTreeDataTable(Id);
                }
            }
        }
        Web 窗体设计器生成的代码#region Web 窗体设计器生成的代码
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
            //
            InitializeComponent();
            base.OnInit(e);
        }

        /**////

        /// 设计器支持所需的方法 - 不要使用代码编辑器修改
        /// 此方法的内容。
        ///

        private void InitializeComponent()
        {
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion
    }
}

本文作者:jiny-z 来源:http://jiny-z.cnblogs.com/
CIO之家 www.ciozj.com 微信公众号:imciow

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