【VBA树控件学习四】编辑与删除TreeView节点

遇见春天

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今天，我们接着来讲一下TreeView树控件。之前，我们已经把新增节点的功能讲完了，接下来我们来讲一下编辑功能与删除功能。

这里我们只修改节点的名称，不变动树的节点，同时，我们需要利用之前学习的新增窗体，所以我们需要来将之前的窗体与代码做一些调整。

1、调整现有窗体

a.我们先将frmAdd窗体名称修改成frmTreeView_Edit

b.在frmTreeView_Edit窗体里添加一个产品编号的文本框，名称为ProductID，同时可用修改成否。

c.在frmTreeView添加两个按钮控件，一个用于打开编辑窗体，名称为：btnEdit，一个用于删除节点：btnDelete，最后在树控件的旁边再添加一个标签控件，用于显示选中树节点的路径。

2、添加/调整代码

接下来，我们就需要来调整代码了。

a.我们先来修改一下frmTreeView的打开新增按钮的代码

    Dim objNode     As NodeSet objNode = Me.TreeView0.SelectedItem '选中某个节点strNodeParentKey = objNode.Key '选中的节点为父节点strNodeKey = Null '当前节点为空strNodeText = Null '当前节点名称为空DoCmd.OpenForm "frmTreeView_Edit", acNormal, , , acFormAdd '打新增窗体

b.在frmTreeView窗体添加一些树控件代码

Private Sub Form_Open(Cancel As Integer)Me.lblPath.Caption = ""
End Sub
Private Sub TreeView0_NodeClick(ByVal Node As Object) '树节点路径Me.lblPath.Caption = "树控件路径：" & Node.FullPathMe.TreeView0.SetFocusEnd Sub
Private Sub TreeView0_GotFocus() '树控件得到焦点Set Me.TreeView0.DropHighlight = Nothing
End Sub
Private Sub TreeView0_LostFocus() '树控件失去焦点Set Me.TreeView0.DropHighlight = Me.TreeView0.SelectedItem
End Sub

c.在frmTreeView添加打开编辑的代码

Private Sub btnEdit_Click()Dim objNode     As NodeSet objNode = Me.TreeView0.SelectedItemIf objNode.Key = "K" ThenExit SubEnd IfstrNodeParentKey = objNode.Parent.KeystrNodeKey = objNode.KeystrNodeText = objNode.TextDoCmd.OpenForm "frmTreeView_Edit", , , , acFormEdit, acDialogobjNode.Text = strNodeTextCall TreeView0_NodeClick(objNode)
End Sub

d.调整一下frmTreeView_Edit的保存与加载事件

'保存按钮
Private Sub btnSave_Click()'判断不能为空If IsNull(Me.ProductName) ThenMsgBox "产品名称不能为空。", vbExclamationMe.ProductName.SetFocusExit SubEnd IfDim rst As Object ' DAO.RecordsetDim strProductID As StringDim strWhere As StringDim strSQL As String'判断上级键值是否为空If Not IsNull(Me.ProductParentID) ThenstrWhere = "ProductParentID='" & Me.ProductParentID & "'"ElsestrWhere = "ProductParentID is null"End If'取到上级键值的最大值strProductID = Nz(DMax("ProductID", "tblProduct", strWhere), "")'生成编号strProductID = Me!ProductParentID & Format(Val(Right(strProductID, 4)) + 1, "0000")'  Debug.Print strProductIDstrSQL = "select * from tblProduct where ProductID='" & Me.ProductID & "'"Set rst = CurrentDb.OpenRecordset(strSQL, 2) '打开记录集If rst.EOF Thenrst.AddNewrst!ProductParentID = Me!ProductParentIDrst!ProductID = strProductIDElserst.EditEnd Ifrst!ProductName = Me!ProductNamerst.UpdatestrNodeText = Me!ProductNameMsgBox "保存成功。", vbInformationIf Me.DataEntry = False ThenDoCmd.Close acForm, Me.NameElseForm_frmTreeView.Form_Load '树重新加载一下Me.ProductName = NullMe.ProductParentID = Replace(strNodeParentKey, "K", "")Me.ProductParentID.RowSource = Me.ProductParentID.RowSource '刷新End Ifrst.CloseSet rst = NothingEnd SubPrivate Sub Form_Load()Me.ProductParentID = Replace(strNodeParentKey, "K", "")If Me.DataEntry Then Exit SubMe.ProductID = Replace(strNodeKey, "K", "")Me.ProductName = strNodeTextMe.ProductParentID.Enabled = IsNull(Me.ProductID)
End Sub

e.在frmTreeView中添加删除代码

Private Sub btnDelete_Click()Dim strMsg          As StringDim objNode             As NodeDim strSQL              As StringDim lngRecordsAffected  As LongSet objNode = Me.TreeView0.SelectedItemIf objNode.Key = "K" ThenExit SubEnd IfIf objNode.Children > 0 ThenMsgBox "该节点下存在子节点，必须先删除所有子节点。", vbExclamationExit SubEnd IfstrMsg = "确定要删除该节点【" & objNode.Text & "】吗？"If MsgBox(strMsg, vbExclamation + vbOKCancel, "删除提示") = vbOK ThenstrSQL = "DELETE FROM tblProduct WHERE ProductID='" & Mid(objNode.Key, 2) & "'"CurrentDb.Execute strSQLMe.TreeView0.Nodes.Remove objNode.KeySet objNode = Me.TreeView0.SelectedItemCall TreeView0_NodeClick(objNode)End If
End Sub

f.在通用模块中添加通用变量名

Public strNodeParentKey    As Variant
Public strNodeKey          As Variant
Public strNodeText         As Variant

3、运行测试

最后，就是运行测试了。

END