ASP.NET中樹形圖的實現(3)

三、修改、移動樹節點

　　由於伺服器控制項不支援滑鼠拖動事件，所以不能象Windows程式那樣通過拖動移動節點，這裡是通過選擇父節點的方式。移動是通過在原位置刪除，新位置添加實現的，要注意在刪除時先儲存節點資訊。

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 ‘移動節點 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’新的父節點的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 ‘由關鍵字尋找節點 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、結束語

　　以上闡述ASP.NET中樹狀顯示的基本方法，以及如何在對樹節點進行維護（增加、刪除、修改、移動）的同時，修改資料庫資料。由於篇幅所限，筆者在此只對基本思路和流程及關鍵步驟作了介紹，並未列出詳細原始碼，讀者可自行完善。需要詳細原始碼者可與我聯絡，本文程式在VS.NET、SQLServer、Windows 2000、IIS5.0下調試通過。