使用 shdocvw.dll 和 mshtml.tlb 自动化 Internet Explorer – 一个案例研究

引言

Microsoft Internet Explorer 附带了一个相当全面的，但文档稀疏的对象模型。 如果您使用过 Access 中的 Web 浏览器控件，那么您已经熟悉 IE 的对象模型的功能。 IE 对象模型中的所有功能（不包括外部支持，如脚本支持等）都由以下两个 DLL 提供

• shdocvw.dll (Microsoft Internet Controls)
• mshtml.tlb (Microsoft HTML 对象库)

您可以自动化 IE 以在本地保存 HTML 文件，检查所有元素，并在运行时解析特定的项目。

这里有一些示例代码，它通过 Internet Explorer Windows 登录到 rediffmail.com，如果用户名和密码有效。

首先，应用程序打开 http://rediff.com 网站。 它在指定位置输入用户名和密码，然后单击“提交”按钮，从而进入收件箱页面。 它还为特定用户打开撰写页面。

该应用程序大量使用 shdocvw.InternetExplorer 对象和 mshtml.Document 对象。

Private Sub Form1_Load(ByVal sender As System.Object, _
            ByVal e As System.EventArgs) Handles MyBase.Load
    Dim wbBrowser As New SHDocVw.InternetExplorer wbBrowser.Visible = True
    wbBrowser.Navigate("http://www.rediff.com", Nothing, Nothing, Nothing, Nothing)
    Do
    Loop Until Not wbBrowser.Busy
    LoginIntoSite(wbBrowser)
    OpennComposePage(wbBrowser)
End Sub

Public Sub LoginIntoSite(ByRef wbBrowser As SHDocVw.InternetExplorer)

    Dim HTMLDoc As mshtml.HTMLDocument

    Do
    Loop Until Not wbBrowser.Busy

    HTMLDoc = wbBrowser.Document

    Dim iHTMLCol As IHTMLElementCollection
    Dim iHTMLEle As IHTMLElement
    Dim str, userName, passwd As String
    
    iHTMLCol = HTMLDoc.getElementsByTagName("input")
    
    ' Type the user name in the username text box
    For Each iHTMLEle In iHTMLCol
        If Not iHTMLEle.getAttribute("name") Is Nothing Then
            str = iHTMLEle.getAttribute("name").ToString
            If str = "login" Then
                iHTMLEle.setAttribute("value", "<VALID USER NAME>")
                Exit For
            End If
        End If
    Next
    
    ' Type the password in the password text box
    For Each iHTMLEle In iHTMLCol
        If Not iHTMLEle.getAttribute("name") Is Nothing Then
            str = iHTMLEle.getAttribute("name").ToString
            If str = "passwd" Then
                iHTMLEle.setAttribute("value", "<VALID PASSWORD>")
                Exit For
            End If
        End If
    Next

    ' Press the submit button
    For Each iHTMLEle In iHTMLCol
        If Not iHTMLEle.getAttribute("name") Is Nothing Then
            If iHTMLEle.outerHTML = "<INPUT type=image" & _ 
                   " height=21 width=26 " & _ 
                   "src=""http://im.rediff.com/" & _ 
                   "uim/rm_go_but.gif"" border=0>" Then
                iHTMLEle.click()
                Exit For
            End If
        End If
    Next

    Do
    Loop Until Not wbBrowser.Busy
End Sub

Public Sub OpenComposePage(ByRef wbBrowser As SHDocVw.InternetExplorer)

    Dim HTMLDoc1 As mshtml.HTMLDocument
    Dim iHtmlCol As IHTMLElementCollection
    Dim iHtmlEle As IHTMLElement

    Do
    Loop Until Not wbBrowser.Busy

    HTMLDoc1 = mshtml.HTMLDocument

    iHtmlCol = HTMLDoc1.getElementsByTagName("a")
    ' Press the anchor tag to open compose page
    For Each iHtmlEle In iHtmlCol
        If Not iHtmlEle.outerText Is Nothing Then
            If iHtmlEle.outerText.ToLower = "write mail".ToLower Then
                iHtmlEle.click()
                Exit For
            End If
        End If
    Next

    Do
    Loop Until Not wbBrowser.Busy
End Sub