ASP.NET中不定级动态菜单的实现

        前日，根据客户需要，要根据如下的表动态生成如下的菜单：表中的数据是动态更新的。

     

        我们平时IEWebContr来做菜单时都是在html中直接输入，也就是说是静态的，现在要做成动态的，而且菜单级数不定，怎么来实现呢？笔者通过研究发现，用 IEWebContr来做菜单时，菜单项可以直接输入，也可以用如下的方法指定从某一个文件中读取菜单项：

〈iewc:TreeView runat="server" ID="Treeview1" NAME="Treeview1"〉
〈iewc:TreeNode id="Treenode1" runat="server" TreeNodeSrc="menuone.txt" Expanded="True" Text="信息类别列表" 〉〈/iewc:TreeNode〉
〈/iewc:TreeView〉

         其中menuone.txt的内容如下：

〈TREENODES〉
〈treenode text='蔬菜' NavigateUrl='xxcb_add.aspx?classname=蔬菜&classid=01'? Target='main1'〉
〈treenode text='白菜' NavigateUrl='xxcb_add.aspx?classname=白菜&classid=0101'?? Target='main1'/〉
〈treenode text='萝卜' NavigateUrl='xxcb_add.aspx?classname=萝卜&classid=0102'?? Target='main1'/〉
〈treenode text='黄花菜' NavigateUrl='xxcb_add.aspx?classname=黄花菜&classid=0103'?? Target='main1'/〉
〈/treenode〉
〈treenode text='水果' NavigateUrl='xxcb_add.aspx?classname=水果&classid=02'? Target='main1'〉
〈treenode text='苹果' NavigateUrl='xxcb_add.aspx?classname=苹果&classid=0201'? Target='main1'〉
〈treenode text='红富士' NavigateUrl='xxcb_add.aspx?classname=红富士&classid=020101'?? Target='main1'/〉
〈treenode text='其它苹果' NavigateUrl='xxcb_add.aspx?classname=其它苹果&classid=020102'?? Target='main1'/〉
〈/treenode〉
〈treenode text='桃子' NavigateUrl='xxcb_add.aspx?classname=桃子&classid=0202'?? Target='main1'/〉
〈treenode text='荔枝' NavigateUrl='xxcb_add.aspx?classname=荔枝&classid=0203'?? Target='main1'/〉
〈/treenode〉
〈treenode text='粮食' NavigateUrl='xxcb_add.aspx?classname=粮食&classid=03'? Target='main1'〉
〈treenode text='大米' NavigateUrl='xxcb_add.aspx?classname=大米&classid=0301'?? Target='main1'/〉
〈treenode text='玉米' NavigateUrl='xxcb_add.aspx?classname=玉米&classid=0302'?? Target='main1'/〉
〈/treenode〉
〈/TREENODES〉

      现在的问题变成了如何将数据表根据“类别号”修改menuone.txt文件。将该过程放在对数据表修改后进行。下面是根据表的内容生成menuone.txt的源代码：
Imports System.IO
       Dim txtwriter As StreamWriter
       txtwriter = File.CreateText(Server.MapPath("\menuone.txt"))
     txtwriter.WriteLine("<TREENODES>")

        Dim objConn As OleDbConnection
        Dim objCmd As OleDbCommand
        Dim objRead As OleDbDataReader
        Dim strSQL, strDSN As String
        Dim strid, strname, strid1, strname1 As String
        Dim strand As String
        strand = "&amp;"

        Dim i, j, k, m As Integer
        i = 0
        j = 0
        k = 0
        m = 0

        strSQL = "select * from class order by classid "

        objConn = New OleDbConnection(ConfigurationSettings.AppSettings("connString"))
        objCmd = New OleDbCommand(strSQL, objConn)
        objCmd.Connection.Open()
        objRead = objCmd.ExecuteReader()

        While objRead.Read()

            If j = 0 Then
                j = Len(Trim(objRead.Item("classid")))
            Else
                strid = strid1
                strname = strname1
                i = Len(Trim(objRead.Item("classid")))

                k = i - j

                Select Case k
                    Case Is > 0
                        txtwriter.WriteLine("<treenode text='" & strname & "' NavigateUrl='adminclass_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'  Target='main2'>")
                    Case Is = 0
                        txtwriter.WriteLine("<treenode text='" & strname & "' NavigateUrl='adminclass_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main2'/>")
                    Case Is < 0
                        txtwriter.WriteLine("<treenode text='" & strname & "' NavigateUrl='adminclass_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main2'/>")
                        'txtwriter.WriteLine("</treenode>")

                        m = k
                        While m < 0
                            txtwriter.WriteLine("</treenode>")
                            m = m + 2
                        End While

                End Select

                j = Len(Trim(objRead.Item("classid")))

            End If

            strid1 = Trim(objRead.Item("classid"))
            strname1 = Trim(objRead.Item("classname"))

        End While

        'strid = strid1
        'strname = strname1
        i = Len(strid)
        k = j - i
        strid = strid1
        strname = strname1
        Select Case k
            Case Is > 0
                txtwriter.WriteLine("<treenode text='" & strname & "' NavigateUrl='adminclass_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main2'/>")
                'txtwriter.WriteLine("</treenode>")

                m = Len(strid) / 2

                While m > 1
                    txtwriter.WriteLine("</treenode>")
                    m = m - 1
                End While
            Case Is = 0
                txtwriter.WriteLine("<treenode text='" & strname & "' NavigateUrl='adminclass_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main2'/>")
                'txtwriter.WriteLine("</treenode>")
                m = Len(strid) / 2

                While m > 1
                    txtwriter.WriteLine("</treenode>")
                    m = m - 1
                End While
            Case Is <= 0
                txtwriter.WriteLine("<treenode text='" & strname & "' NavigateUrl='adminclass_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main2'/>")
                'txtwriter.WriteLine("</treenode>")

                m = Len(strid) / 2

                While m > 1
                    txtwriter.WriteLine("</treenode>")
                    m = m - 1
                End While

        End Select
        txtwriter.WriteLine("</TREENODES>")
        txtwriter.Close()

     这样menuone.txt就按要求生成了菜单源文件。
如有更好的办法，请与我联系谢谢。QQ：14959288 6

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