vb.net 教程 4-10 XML文件操作 4-3

╰半夏微凉° 2022-09-10 12:13 125阅读 0赞

添加数据由于要调用到别的窗体，所以先来看“增加检测地址”窗体中的代码：

设置3个公共变量，此窗体关闭时需要传递给主窗体：

Public addrName As String  
    Public addrInfo As String  
    Public addrType As String  
窗口载入时：

Private Sub FormAddr\_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load  
        AddHandler rbPC.CheckedChanged, AddressOf clickrbPC  
        AddHandler rbWww.CheckedChanged, AddressOf clickrbWww  
        txtName.Focus()  
    End Sub  
   
    Private Sub clickrbPC(ByVal sender As Object, ByVal e As System.EventArgs)  
        If rbPC.Checked = True Then  
            If txtAddr.Text.Length >= 7 Then  
                If txtAddr.Text.Trim.Substring(0, 7) = "http://" Then  
                    txtAddr.Text = txtAddr.Text.Substring(7, txtAddr.Text.Length - 7)  
                End If  
            End If  
        End If  
    End Sub  
   
    Private Sub clickrbWww(ByVal sender As Object, ByVal e As System.EventArgs)  
        If rbWww.Checked = True Then  
            If txtAddr.Text.Length > 7 Then  
                If txtAddr.Text.Trim.Substring(0, 7) <> "http://" Then  
                    txtAddr.Text = "http://" & txtAddr.Text  
                End If  
            Else  
                txtAddr.Text = "http://" & txtAddr.Text  
            End If  
   
        End If  
    End Sub

按下确定按钮

Private Sub btnOK\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click  
        Dim errMsg As String = checkAddr()  
        If errMsg = "" Then  
            addrName = txtName.Text.Trim  
            addrInfo = txtAddr.Text.Trim  
            If rbPC.Checked = True Then addrType = "PC" Else addrType = "WWW"  
            Me.Close()  
            Me.DialogResult = Windows.Forms.DialogResult.OK  
        Else  
            MessageBox.Show(errMsg)  
            Exit Sub  
        End If  
    End Sub  
   
    Private Function checkAddr() As String  
        If txtName.Text.Trim = "" Then  
            Return "名称不能为空"  
        End If  
   
        If txtAddr.Text.Trim = "" Then  
            Return "地址不能为空"  
        End If  
   
        Return ""  
    End Function

按下“取消”按钮：

Private Sub btnCancel\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click  
        Me.Close()  
        Me.DialogResult = Windows.Forms.DialogResult.Cancel  
    End Sub

主窗体中的“增加地址”：

Private Sub btnAdd\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click  
        Dim addrname As String = ""  
        Dim addrinfo As String = ""  
        Dim addrtype As String = ""  
   
        Dim frmAddr As New FormAddr  
        If frmAddr.ShowDialog <> Windows.Forms.DialogResult.OK Then  
            frmAddr.Dispose()  
            Exit Sub  
        End If  
   
        addrname = frmAddr.addrName  
        addrinfo = frmAddr.addrInfo  
        addrtype = frmAddr.addrType  
        Dim xdoc As New XmlDocument()  
        Try  
            xdoc.Load(xmlfile)  
            Dim addrNodes As XmlNode  
            addrNodes = xdoc.SelectSingleNode("//addrdata")  
   
            Dim xmlEleParent As XmlElement = xdoc.CreateElement("addrlist")  
            Dim xmlEleChildName As XmlElement = xdoc.CreateElement("name")  
            xmlEleChildName.InnerText = addrname  
            xmlEleParent.AppendChild(xmlEleChildName)  
   
            Dim xmlEleChildaddr As XmlElement = xdoc.CreateElement("addr")  
            xmlEleChildaddr.InnerText = addrinfo  
            xmlEleParent.AppendChild(xmlEleChildaddr)  
   
            Dim xmlEleChildtype As XmlElement = xdoc.CreateElement("type")  
            xmlEleChildtype.InnerText = addrtype  
            xmlEleParent.AppendChild(xmlEleChildtype)  
   
   
            addrNodes.AppendChild(xmlEleParent)  
            xdoc.Save(xmlfile)  
   
        Catch ex As Exception  
            tsslInfo.Text = "增加地址失败：" & ex.Message  
        End Try  
   
        frmAddr.Dispose()  
   
        lvCheck.Items.Clear()  
        '载入xml中的数据  
        If loadXmlData() = False Then  
            Exit Sub  
        End If  
   
    End Sub

主窗体中的“删除地址”按钮：

Private Sub btnDel\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDel.Click  
        If lvCheck.SelectedItems.Count < 1 Then  
            tsslInfo.Text = "请先选择一项"  
            Exit Sub  
        End If  
   
        Dim lvAddrname As String  
        Dim lvAddrInfo As String  
        Dim lvAddrType As String  
   
        lvAddrname = lvCheck.SelectedItems(0).SubItems(1).Text  
        lvAddrInfo = lvCheck.SelectedItems(0).SubItems(3).Text  
        lvAddrType = lvCheck.SelectedItems(0).SubItems(2).Text  
   
        Dim xd As New XmlDocument()  
        Try  
            xd.Load(xmlfile)  
            Dim rootNode As XmlNode = xd.SelectSingleNode("//addrdata")  
   
            Dim addrNodes As XmlNodeList  
            addrNodes = rootNode.ChildNodes  'xd.SelectNodes("//addrdata/addrlist")  
            Dim i As Integer = 0  
            Dim addrname As String = ""  
            Dim addrinfo As String = ""  
            Dim addrtype As String = ""  
            If addrNodes.Count > 0 Then  
                For Each addrNode As XmlNode In addrNodes  
                    i += 1  
                    Dim addrNodeInfos As XmlNodeList  
                    addrNodeInfos = addrNode.ChildNodes  
   
                    addrname = addrNodeInfos(0).InnerText  
                    addrinfo = addrNodeInfos(1).InnerText  
                    addrtype = addrNodeInfos(2).InnerText  
   
                    If (addrname = lvAddrname) And (addrinfo = lvAddrInfo) And (addrtype = lvAddrType) Then  
                        rootNode.RemoveChild(addrNode)  
                    End If  
                Next  
            End If  
            xd.Save(xmlfile)  
   
            lvCheck.Items.Clear()  
            '载入xml中的数据  
            If loadXmlData() = False Then  
                Exit Sub  
            End If  
   
        Catch ex As Exception  
            tsslInfo.Text = "删除地址失败：" & ex.Message  
        End Try  
   
    End Sub

由于.net平台下C\#和vb.NET很相似，本文也可以为C\#爱好者提供参考。

学习更多vb.net知识，请参看[vb.net教程][vb.net]目录

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