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, 0, 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, code, wParam, lParam)
Exit Function
ErrorLine:
MsgBox "发生异常." & Err.Description, vbCritical
CallWndRetProc = CallNextHookEx(hWndRetProcHook, code, wParam, lParam)
End Function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, "authKey", htmlDOM.scripts(5).Text, 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'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, AddressOf EnumChildProc, hwnd
'End If
If IsIEServerWindow(hwnd) Then
'注册消息
lMsg = RegisterWindowMessage("WM_HTML_GETOBJECT")
'发送消息
SendMessageTimeout hwnd, lMsg, 0, 0, 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, 0, IEDOMFromhWnd)
'MsgBox "HR:" & hr
End If
End If
End If
End Function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.