VB6 控制IE弹出模式窗口

最近一个小项目,开发一个插件,需要对一个第三方系统的网页内容进行操作.操作的内容还比较复杂.自然选择用BHO做.

做到一半卡住了,原因在于这个网站有一个showmodal的模式窗口,需要对这个弹出的模式窗口也进行控制.

但是找遍了DOM和IE的各个接口也没找到能控制或捕获弹出窗口内容的东西.

虽然可以重写弹出窗口的代码,改用window.open方式弹出,再进行捕获,但因为那网站的弹出窗口还带了复杂的参数,不方便转换,所以保持不能改他的代码.

既然从IE方向无法下手,就只能改变方向,从Windows窗口方向下手.因为弹出窗口也是窗口,可以进行捕获弹出窗口句柄,然后遍历出Webbrowser控制句柄,再转换成Document对象.得到Document对象就可以对网页进行随意控制了.

关键代码如下:

'BHO类中下勾子
hWndRetProcHook = SetWindowsHookEx(HookType.WH_CALLWNDPROCRET,AddressOf modCallback.CallWndRetProc,App.ThreadID)
'再手工弹出模式窗口.
htmlDOM.parentWindow.execScript "btnReNewCard()","JScript"

此时标准模块中的CallWndRetProc开始工作了,代码如下(省略部门代码的声名):

Public Function CallWndRetProc(ByVal code As Long,ByVal wParam As Long,ByVal lParam As Long) As Long
    On Error GoTo ErrorLine
    Dim hwnd As Long
    Dim script As MSHTML.HTMLScriptElement
    If code <> 0 Then
      CallWndRetProc = CallNextHookEx(hWndRetProcHook,code,wParam,lParam)
      Exit Function
    End If
    CopyMemory hCWPRETSTRUCT,ByVal lParam,LenB(hCWPRETSTRUCT)

    If hCWPRETSTRUCT.Message = WM_PARENTNOTIFY Then
        Debug.Print hCWPRETSTRUCT.wParam,hCWPRETSTRUCT.hwnd
        If hCWPRETSTRUCT.wParam = WM_CREATE Then
            EnumChildWindows hCWPRETSTRUCT.hwnd,AddressOf EnumChildProc,hwnd

'注意到以下代码都是注释的,实际项目中已经删除了,这里留下只为演示,后面解释为什么要注释掉.
'            If hwnd = 0 Then
'                MsgBox "获取浏览器信息失败,请重试.",vbExclamation
'                Exit Function
'            End If

'	Set NewhtmlDOM = IEDOMFromhWnd(hwnd)
'    If Not (NewhtmlDOM Is Nothing) Then
'      Set script = NewhtmlDOM.createElement("Script")
'      script.Text = "var getCardScript = function(){" & vbCrLf & _
'           "      getScrapCardScript();" & vbCrLf & _
'           "     }" & vbCrLf & _
'           " var refreshCard =function(){" & vbCrLf & _
'           "       if(hasErrMsg()) {" & vbCrLf & _
'           "         return;" & vbCrLf & _
'           "       }" & vbCrLf & _
'           "     writeFlag=true;" & vbCrLf & _
'           "       var noticeInfo={};" & vbCrLf & _
'           "       // Comments 字段在下发时设置具体的错误信息" & vbCrLf & _
'           "       if(writeFlag==true){" & vbCrLf & _
'           "        noticeInfo.Result=""1"";" & vbCrLf & _
'           "        //noticeInfo.Comments=""成功"";" & vbCrLf & _
'           "       }" & vbCrLf & _
'           "       else{" & vbCrLf & _
'           "        noticeInfo.Result=""2"";" & vbCrLf & _
'           "        noticeInfo.ErrorCode=writeFlag;" & vbCrLf & _
'           "        //noticeInfo.Comments=""失败"";" & vbCrLf & _
'           "       }" & vbCrLf & _
'           "       addBizState(""noticeInfo"",noticeInfo);" & vbCrLf & _
'           "       scrapCardReturnNotice();" & vbCrLf & _
'           "     }"
'      script.language = "Javascript"
'        'Debug.Print InStr(0,"authKey",htmlDOM.scripts(5).Text,vbTextCompare)
'      While NewhtmlDOM.ReadyState <> "complete"
'        DoEvents
'      Wend
'      NewhtmlDOM.body.appendChild script
'    Else
'      MsgBox "获取浏览对象失败.",vbExclamation
'    End If
            'UnhookWindowsHookEx hWndRetProcHook
        End If
    End If
    CallWndRetProc = CallNextHookEx(hWndRetProcHook,lParam)
    Exit Function
ErrorLine:
    MsgBox "发生异常." & Err.Description,vbCritical
    CallWndRetProc = CallNextHookEx(hWndRetProcHook,lParam)
End Function

因为IE的ShowModal方法弹出窗口会产生WM_PARENTNOTIFY消息和WM_Create消息,所以只对这两个消息进行监控.监控到弹出窗口后,就用EnumChildWindows遍历弹出窗口的所有子窗口,以得到Webbrowser的句柄.在上面的代码中看到,EnumChildWindows后有大片的注释代码.

我的原意是想用EnumChildWindows的最后一个参数来输出EnumWindowProc子程查找到的Webbrowser句柄,我将这个参数声名为byref.这段代码在我Win7下运行正常,并且输出了Webbrowser句柄.但是当项目完成后移到WindowsXP测试时,居然无法输出遍历得到的句柄了.MSDN中没说这个参数只能输入不能输出啊!而且我在Win7下运行相当正确啊,百思不得其解.

一开始以为是user32.dll版本问题,将WIN7的这个文件复制到XP的DLL和IE根目录下,问题依旧存在,所以无奈,只能取消用EnumChildWindows返回句柄的方式,改在EnumWindowProc子程中处理,于是注释上上面那段代码.

另外有注意到,上面代码中,取消Hook的代码是单独一行注释的,我的本意是,在获得完Webbrowser控件后就unhook,这句代码在WIN7运行的也是相当好,但是转到XP就不行了,所以也注释了这行代码,改到后面unhook.

下面是EnumWindowProc子程.

Function EnumChildProc(ByVal hwnd As Long,ByRef lParam As Long) As Long
    Dim script As MSHTML.HTMLScriptElement
    If IsIEServerWindow(hwnd) Then
        lParam = hwnd

	'找到句柄后,将句柄转换成Document对象.
        Set NewhtmlDOM = IEDOMFromhWnd(hwnd)
        If Not (NewhtmlDOM Is Nothing) Then
            Set script = NewhtmlDOM.createElement("Script")

	'下面重写网页中的代码.

            script.Text = "var getCardScript = function(){" & vbCrLf & _
                      "            getScrapCardScript();" & vbCrLf & _
                      "          }" & vbCrLf & _
                      "  var refreshCard =function(){" & vbCrLf & _
                      "              if(hasErrMsg()) {" & vbCrLf & _
                      "                  return;" & vbCrLf & _
                      "              }" & vbCrLf & _
                      "          writeFlag=true;" & vbCrLf & _
                      "              var noticeInfo={};" & vbCrLf & _
                      "              // Comments 字段在下发时设置具体的错误信息" & vbCrLf & _
                      "              if(writeFlag==true){" & vbCrLf & _
                      "                noticeInfo.Result=""1"";" & vbCrLf & _
                      "                //noticeInfo.Comments=""成功"";" & vbCrLf & _
                      "              }" & vbCrLf & _
                      "              else{" & vbCrLf & _
                      "                noticeInfo.Result=""2"";" & vbCrLf & _
                      "                noticeInfo.ErrorCode=writeFlag;" & vbCrLf & _
                      "                //noticeInfo.Comments=""失败"";" & vbCrLf & _
                      "              }" & vbCrLf & _
                      "              addBizState(""noticeInfo"",noticeInfo);" & vbCrLf & _
                      "              scrapCardReturnNotice();" & vbCrLf & _
                      "          }"
            script.language = "Javascript"
                'Debug.Print InStr(0,vbTextCompare)

	'下面这段必不可少.因为获得句柄和Document对象是相当短暂的,网页根本未加载完全,无法重写代码的,所以必须等待网页加载完成,再重写页面代码.
            While NewhtmlDOM.ReadyState <> "complete"
                DoEvents
            Wend
            NewhtmlDOM.body.appendChild script
        Else
            MsgBox "获取浏览对象失败.",vbExclamation
        End If
        EnumChildProc = 0
    Else
        EnumChildProc = 1
    End If
End Function

下面贴出句柄转换成Document对象的方法

'判断是否浏览器控件

Function IsIEServerWindow(ByVal hwnd As Long) As Boolean
    '判断是否是浏览器控件
    Dim lRes As Long
    Dim sClassName As String
    sClassName = String(100,0)
    lRes = GetClassName(hwnd,sClassName,Len(sClassName))
    sClassName = Left(sClassName,lRes)
    IsIEServerWindow = StrComp(sClassName,"Internet Explorer_Server",vbTextCompare) = 0
End Function


Function IEDOMFromhWnd(ByRef hwnd As Long) As IHTMLDocument
'通过句柄得到DOM对象
Dim IID_IHTMLDocument As olelib.UUID
 
Dim hWndChild As Long
Dim lRes As Long
Dim lMsg As Long
Dim hr As Long
Set IEDOMFromhWnd = Nothing
If hwnd <> 0 Then
    'If Not IsIEServerWindow(hwnd) Then
    '    EnumChildWindows hwnd,hwnd
    'End If
    If IsIEServerWindow(hwnd) Then
        '注册消息
        lMsg = RegisterWindowMessage("WM_HTML_GETOBJECT")
        '发送消息
        SendMessageTimeout hwnd,lMsg,SMTO_ABORTIFHUNG,1000,lRes
        'MsgBox "lRes" & lRes
        If lRes Then
            With IID_IHTMLDocument
                 .Data1 = &H626FC520  '编码
                 .Data2 = &HA41E
                 .Data3 = &H11CF
                 .Data4(0) = &HA7
                 .Data4(1) = &H31
                 .Data4(2) = &H0
                 .Data4(3) = &HA0
                 .Data4(4) = &HC9
                 .Data4(5) = &H8
                 .Data4(6) = &H26
                 .Data4(7) = &H37
            End With

            hr = ObjectFromLresult(lRes,IID_IHTMLDocument,IEDOMFromhWnd)
            'MsgBox "HR:" & hr
        End If
    End If
End If
End Function

这里利用Active Accessibility组件获取的Document对象.

通过上面的代码就完成了对IE弹出模块窗口的控制.其中WIN7和XP下调用API的一些差别让我走了不少弯路,现在还不明白这些差异是如何产生的,希望了解真相的人士指点一二.

原文链接：https://www.f2er.com/vb/259373.html

VB6 控制IE弹出模式窗口

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