ASP.NET中不定级动态菜单的实

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.MapPathstrpath ("\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='xxcb_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'  Target='main1'>")
Case Is = 0
txtwriter.WriteLine("<treenode text='" & strname & "' NavigateUrl='xxcb_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main1'/>")
Case Is < 0
txtwriter.WriteLine("<treenode text='" & strname & "' NavigateUrl='xxcb_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main1'/>")
'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='xxcb_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main1'/>")
'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='xxcb_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main1'/>")
'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='xxcb_add.aspx?classname=" & strname & "" & strand & "classid=" & strid & "'   Target='main1'/>")
'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。