Treeview选择asp.net

Question

我有一个树视图，它从数据库加载数据以显示产品的类别和子类别。 树视图中有4个级别的类别。 我希望当用户单击某个项目以在网格中显示这些类别和子类别（所选）中的所有产品时 这是代码

      FilePath = "moneyfest.mdb"

    Dim CNnwind As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & FilePath & ";Persist Security Info=False") '<==== CHANGE HERE 
    Dim DAdtCat As New OleDbDataAdapter("SELECT *  FROM Categories ", CNnwind)
    Dim DAdSub1 As New OleDbDataAdapter("SELECT * FROM ProductSubCategories where ParentCategory in (select CategoryID from Categories )", CNnwind)
    Dim DAdSub2 As New OleDbDataAdapter("Select * FROM ProductSubCategories2 where ParentCategory in (SELECT id FROM ProductSubCategories where id in (select CategoryID from categories ))", CNnwind)
    Dim DAdSub3 As New OleDbDataAdapter("Select * FROM ProductSubCategories3 where ParentCategory in (SELECT id FROM ProductSubCategories2 where ParentCategory in (SELECT id FROM ProductSubCategories where ParentCategory in (select CategoryID from categories )))", CNnwind)

    DSNWind = New DataSet()
    CNnwind.Open()
    DAdtCat.Fill(DSNWind, "dtCat")
    DAdSub1.Fill(DSNWind, "dtSub1")
    DAdSub2.Fill(DSNWind, "dtSub2")
    DAdSub3.Fill(DSNWind, "dtSub3")
    CNnwind.Close()

    'Create a data relation object to facilitate the relationship between the Customers and Orders data tables.
    DSNWind.Relations.Add("CustToOrd", DSNWind.Tables("dtCat").Columns("CategoryID"), DSNWind.Tables("dtSub1").Columns("ParentCategory"))
    DSNWind.Relations.Add("OrdToDet", DSNWind.Tables("dtSub1").Columns("id"), DSNWind.Tables("dtSub2").Columns("ParentCategory"))
    DSNWind.Relations.Add("OrdToDetDet", DSNWind.Tables("dtSub2").Columns("id"), DSNWind.Tables("dtSub3").Columns("ParentCategory"))
    '''''''''''''''''''''''
    TreeView2.Nodes.Clear()
    Dim i, n As Integer
    Dim parentrow As DataRow
    Dim ParentTable As DataTable
    ParentTable = DSNWind.Tables("dtCat")

    For Each parentrow In ParentTable.Rows
        Dim parentnode As TreeNode
        parentnode = New TreeNode(parentrow.Item(1))
        TreeView2.Nodes.Add(parentnode)
        ''''populate child'''''
        '''''''''''''''''''''''
        Dim childrow As DataRow
        Dim childnode As TreeNode
        childnode = New TreeNode()
        For Each childrow In parentrow.GetChildRows("CustToOrd")
            childnode = parentnode.Nodes.Add(childrow(1))
            childnode.Tag = childrow("SubCategoryName")
            ''''populate child2''''
            ''''''''''''''''''''''''''
            Dim childrow2 As DataRow
            Dim childnode2 As TreeNode
            Dim childrow3 As DataRow
            Dim childnode3 As TreeNode
            childnode2 = New TreeNode()
            For Each childrow2 In childrow.GetChildRows("OrdToDet")
                childnode2 = childnode.Nodes.Add(childrow2(1))
                childnode3 = New TreeNode()
                For Each childrow3 In childrow2.GetChildRows("OrdToDetDet")
                    childnode3 = childnode2.Nodes.Add(childrow3(1))

                Next childrow3
            Next childrow2
            ''''''''''''''''''''''''

        Next childrow
        '''''''''''''''
    Next parentrow