使用递归从数据库读取数据来动态建立菜单
类别: ASP.NET教程 
MenBh MenText Bhparent
0001 文件
0002 编辑
0005 打开 0001
0006 新建 0001
0011 access数据库 0006
0012 VFP的Dbf 0006
0013 剪切 0002
0014 复制 0002
0015 完全复制 0014
Private m As New MainMenu()
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim conn As New SqlConnection(\"server=localhost;uid=sa;pwd=;database=jiang\")
Dim cmd As New SqlCommand(\"select * from a_menu \", conn)
Dim ds As New DataSet()
Dim sqldpr As New SqlDataAdapter(cmd)
sqldpr.Fill(ds, \"menu\")
Me.DataGrid1.DataSource = ds.Tables(\"menu\")
\'创建关系
Dim dr As New DataRelation(\"self_menu\", ds.Tables(\"menu\").Columns(\"MenBh\"), ds.Tables(\"menu\").Columns(\"Bhparent\"))
ds.Relations.Add(dr)
Dim r1 As DataRow
\'查找最高的菜单级别,也就是Bhparent列为空的行
For Each r
If r1.IsNull(\"Bhparent\") Then
addmenuitem(r1, Nothing)
End If
Next
Me.Menu = m \'指定主窗体菜单
End Sub
\'递归函数
Private Sub addmenuitem(ByVal r As DataRow, ByVal item As MenuItem)
Dim mi As MenuItem
\'如果是最外层菜单，要直接添加
If item Is Nothing Then
mi = m.MenuItems.Add(r.Item(\"MenText\"))
Else \'如果是下级菜单要在菜单项的上级添加
mi = item.MenuItems.Add(r.Item(\"MenText\"))
End If
Dim r2 As DataRow
For Each r
addmenuitem(r2, mi)
Next
End Sub
\'--------------------------------------------------------一种方法的改进
‘/////////////////////////////////////////////////////////////////////////////////////
‘继承自menuitem的类
‘/////////////////////////////////////////////////////////////////////////////////////
Public Class mymenuitem
Inherits System.Windows.Forms.MenuItem
Public Sub New(ByVal s As String, ByVal tag As String)
MyBase.New()
Me.Text = s
m_tag = tag
End Sub
Private m_tag As String
Public Property tag() As String
Get
Return m_tag
End Get
Set(ByVal Value As String)
m_tag = Value
End Set
End Property
End class
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