在线等待,树型控件问题

[cxyPioneer]

怎样才能实现 动态 添加,删除节点,子节点,并且能够把数据保存到数据库中,最好能有一些代码

[jxpanda]

一、树的建立

具体方法是：创建一个数据库，设计树图信息表TREE_INFO，包含NODEID、PARENTID、NODENAME、ADDERSS、ICON字段，其它字段根据实际业务而定，节点名称NODENAME将在树型控件的节点上显示，NODEID字段保存节点的唯一标识号，PARENTID表示当前节点的父节点号，标识号组成了一个“链表”，记录了树上节点的结构。设计一个Web窗体其上放置TreeView控件。
Private Sub CreateDataSet()’建立数据集
Dim myConn As New SqlConnection()
Dim myCmd As New SqlCommand("select NODEID,NODENAME,PARENTID,ADDRESS,ICON from Tree_info", myConn)
Dim myDataAdapter As New SqlDataAdapter()
myConn.ConnectionString = Application("connectstring")
myCmd.CommandText = ""
myCmd.Connection = myConn
myDataAdapter.SelectCommand = myCmd
myDataAdapter.Fill(ds, "tree")
End Sub
建树的基本思路是：从根节点开始递归调用显示子树
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
CreateDataSet()
intiTree(TreeView1.Nodes, 0)
End Sub
Private Sub intiTree(ByRef Nds As TreeNodeCollection, ByVal parentId As Integer)
Dim dv As New DataView()
Dim drv As DataRowView
Dim tmpNd As TreeNode
Dim intId As Integer
dv.Table = ds.Tables("tree")
dv.RowFilter = "PARENTID=’" & parentId & "’"
For Each drv In dv
tmpNd = New TreeNode()
strId = drv("NODE_ID")
tmpNd.ID = strId
tmpNd.Text = drv("NODE_NAME ")
tmpNd.ImageUrl = drv("ICON").ToString
Nds.Add(tmpNd)
intiTree(Nds(Nds.Count - 1).Nodes, intId)
Next
End Sub

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

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