ASP.NET中树形图的实现(2)

     二、增加、删除树节点
  　　单纯在Treeview 上增加、删除、修改节点只需用Nodes属性的Add、 Remove、等方法即可，值得注意的地方是VS.NET中Treeview的Nodes集合与VS6.0中的区别，VS6.0中的是一个大的集合，而VS.NET中的是分层的每个Node下都有Nodes属性。增加、删除、修改树节点时与VS6.0相比有很大差别，特别是删除时。
  
  Private Sub ButAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButAdd.Click’在选定的节点下添加子节点
  Dim tmpNd As New TreeNode(), NdSel As TreeNode
  tmpNd.ID = GetNewId()
  NdSel = TreeView1.GetNodeFromIndex(TreeView1.SelectedNodeIndex)’选中的节点
  tmpNd.Text = "新节点"
  NdSel.Nodes.Add(tmpNd)
  Dim myRow As DataRow
  myRow = ds.Tables("tree").NewRow()
  myRow("NODE_NAME") = tmpNd.ID
  myRow("NODE_DEscript") = "新节点" & tmpNd.ID & "_" & NdSel.ID
  myRow("PARENT_NAME") = NdSel.ID
  ds.Tables("tree").Rows.Add(myRow)
  End Sub
  Private Sub ButDele_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles ButDele.Click’删除选中的节点
  Dim idx As String = TreeView1.SelectedNodeIndex()
  GetNdCol(idx).Remove(TreeView1.GetNodeFromIndex(idx))
  Dim dv As New DataView(), recNo As Integer
  dv.Table = ds.Tables("tree")
  dv.RowFilter= "NODEID=" & NdId
  dv.Delete(0)
  End Sub
  Private Function GetNdCol(ByVal idx As String) As TreeNodeCollection
  ‘获得选中节点的父节点的Nodes集合
  Dim cnt As Integer, i As Integer
  Dim tmpNds As TreeNodeCollection
  Dim idxs() As String
  idxs = Split(idx, ".")
  cnt = UBound(idxs)
  If cnt = 0 Then
  tmpNds = TreeView1.Nodes
  Else
  tmpNds = TreeView1.Nodes(CInt(idxs(0))).Nodes
  For i = 1 To cnt - 1
  tmpNds = tmpNds(CInt(idxs(i))).Nodes
  Next
  End If
  Return tmpNds
  End Function