ASP.NET不定级动态菜单的实现

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 = "&"

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。