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()