ASP.NET中树形图的实现

三、修改、移动树节点

　　由于服务器控件不支持鼠标拖动事件，所以不能象Windows程序那样通过拖动移动节点，这里是通过选择父节点的方式。移动是通过在原位置删除，新位置添加实现的，要注意在删除时先保存节点信息。

Private Sub TreeView1_SelectedIndexChange(ByVal sender As Object, ByVal e As Microsoft.Web.UI.WebControls.TreeViewSelectEventArgs) Handles TreeView1.SelectedIndexChange Dim dv As New DataView() dv.Table = ds.Tables("tree") Dim tmpNd As TreeNode = TreeNdSel(e.OldNode), tmpNds As TreeNodeCollection dv.RowFilter= "NODEID=" & tmpNd.ID dv(0)("NODE_DESCRIPT") = Me.TextBox1.Text dv(0)("ADDRESS") = Me.TextBox2.Text dv(0)("TARGET") = Me.TextBox3.Text dv(0)("ICON") = Me.TextBox4.Text If dv(0)("PARENTID").ToString <> Me.DropDownList1.SelectedItem.Value Then ‘移动节点 dv(0)("PARENT_NAME") = Me.DropDownList1.SelectedItem.Value If Me.DropDownList1.SelectedItem.Value = "ROOT" Then tmpNds = TreeView1.Nodes Else tmpNds = FromIdToNode(Me.DropDownList1.SelectedItem.Value, TreeView1.Nodes).Nodes’新的父节点的Nodes集合 End If GetNdCol(e.OldNode).Remove(tmpNd) tmpNds.Add(tmpNd) End If tmpNd.Text = Me.TextBox1.Text tmpNd.ImageUrl = Me.TextBox4.Text tmpNd = TreeView1.GetNodeFromIndex(TreeView1.SelectedNodeIndex) dv.RowFilter= "NODEID=" & tmpNd.ID Me.TextBox1.Text = dv(0)("NODENAME").ToString Me.TextBox2.Text = dv(0)("ADDRESS").ToString Me.TextBox3.Text = dv(0)("TARGET").ToString Me.TextBox4.Text = dv(0)("ICON").ToString End Sub Private Function FromIdToNode(ByVal ID As String, ByVal Nds As TreeNodeCollection) As TreeNode ‘由关键字查找节点 Dim i As Integer Dim tmpNd As TreeNode, tmpNd1 As TreeNode For Each tmpNd In Nds If tmpNd.ID = ID Then Return tmpNd Exit Function End If tmpNd1 = FromIdToNode(ID, tmpNd.Nodes) If Not (tmpNd1 Is Nothing) Then Return tmpNd1 Exit Function End If Next Return Nothing End Function

　　四、结束语

　　以上阐述ASP.NET中树状显示的基本方法，以及如何在对树节点进行维护（增加、删除、修改、移动）的同时，修改数据库数据。由于篇幅所限，笔者在此只对基本思路和流程及关键步骤作了介绍，并未列出详细源代码，读者可自行完善。需要详细源代码者可与我联系，本文程序在VS.NET、SQLServer、Windows 2000、IIS5.0下调试通过。

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