八、更加深入的例子

同12章中通过 HtmlElement类 或者其他方法获取网页上元素信息，

我们也可以通过获得 mshtml.IHTMLDocument2 来获得IE窗口网页元素信息。

这里偷个懒，主要代码同上一小节 vb.net 教程 20-3 控制Ie浏览器 8

但是将ListIe设置为窗体级变量：

Dim listIe As ArrayList

对应列表按钮代码：

    Private Sub cbListIE_Click(sender As Object,e As EventArgs) Handles cbListIE.Click
        listIe = New ArrayList
        listIe = getIhtmlDoc()
        If listIe.Count > 0 Then
            For i As Integer = 0 To listIe.Count - 1
                Dim subList As New ListViewItem()
                subList.Text = i.ToString
                Dim iedocInfo As New IeDocStructure
                iedocInfo = CType(listIe.Item(i),IeDocStructure)
                subList.SubItems.Add(iedocInfo.title)
                subList.SubItems.Add(iedocInfo.url)
                lvListIE.Items.Add(subList)
            Next
        End If
    End Sub

所举例子采用的是 http://www.qqrec.com/vblessons/vbnet20-2-1.htm

获得文本框内的信息代码如下：

    Private Sub btnInfo_Click(sender As Object,e As EventArgs) Handles btnInfo.Click
        If lvListIE.SelectedIndices.Count < 1 Then
            MessageBox.Show("尚未选择一行数据")
            Exit Sub
        End If

        Dim selectedIndex As Integer
        selectedIndex = lvListIE.SelectedIndices.Item(0)
        Dim ieInfo As IeDocStructure
        Dim ie_SHwnd As Integer
        ieInfo = CType(listIe.Item(selectedIndex),IeDocStructure)
        ie_SHwnd = ieInfo.IE_SHwnd

        '获得IHTMLDocument2接口
        Dim IEdoc As mshtml.IHTMLDocument2
        IEdoc = getDocumentfromIES(ie_SHwnd)

        Dim studentname As String = ""
        Dim studentage As String = ""

        Dim ieElement As mshtml.IHTMLElement
        For Each ieElement In IEdoc.all
            Select Case ieElement.id
                Case "studentname"
                    studentname = ieElement.getAttribute("value")
                Case "studentage"
                    studentage = ieElement.getAttribute("value")
            End Select
        Next

        MessageBox.Show("学生名称：" & studentname & vbCrLf & "学生年龄：" & studentage)
    End Sub

运行结果如下图（注意，笔者偷懒直接选择正确的网页，如果选择别的网页不能返回结果的）

不管Ie窗体是被遮挡或者最小化，都会获得正确的结果。

当然请注意：切勿用于做坏事

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 目录