主题：授权目录树的四级代码怎么写

老师，

   目录树的授权，目录树是四级的，代码怎么写呢？

此主题相关图片如下：四级的目录树.png

Dim trv1 As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim trv2 As WinForm.TreeView = e.Form.Controls("TreeView2")
Dim dr As DataRow
Select Case e.node.Level
    Case 0
        dr = DataTables("授权表").Find("功能主模块 = '" & e.Node.Name & "' And 权限 Is Null")
    Case 1
        dr = DataTables("授权表").Find("功能主模块 = '" & e.Node.Name & "' And  一级模块 = '" & e.Node.ParentNode.Name & "' And  权限 = '" & e.Node.Name & "'")
    Case 2
        dr = DataTables("授权表").Find("功能主模块 = '" & e.Node.Name & "' And  一级模块 = '" & e.Node.ParentNode.Name & "' And  二级模块 = '" & e.Node.ParentNode.ParentNode.Name & "' And  权限 = '" & e.Node.Name & "'")
    Case 3
        dr = DataTables("授权表").Find("功能主模块 = '" & e.Node.Name & "' And  一级模块 = '" & e.Node.ParentNode.Name & "' And  二级模块 = '" & e.Node.ParentNode.ParentNode.Name & "'And  权限 = '" & e.Node.ParentNode.ParentNode.ParentNode.Name & "'")
End Select
Dim nms As New List(of String)
If dr IsNot Nothing AndAlso dr.IsNull("用户") = False
    nms.AddRange(dr("用户").Split(","))
End If
For Each nd As WinForm.TreeNode In trv2.AllNodes
    nd.Checked = nms.Contains(nd.Name)
Next