{var%20f='http://v.t.sina.com.cn/share/share.php?appkey=1515056452',u=z||d.location,p=['&url=',e(u),'&title=',e(t||d.title),'&source=',e(r),'&sourceUrl=',e(l),'&content=',c||'gb2312','&pic=',e(p||'')].join('');function%20a(){if(!window.open([f,p].join(''),'mb',['toolbar=0,status=0,resizable=1,width=440,height=430,left=',(s.width-440)/2,',top=',(s.height-430)/2].join('')))u.href=[f,p].join('');};if(/Firefox/.test(navigator.userAgent))setTimeout(a,0);else%20a();})(screen,document,encodeURIComponent,'','','https://www.manongdao.com/data/attach/logo/logo.png', '推荐 Root（大扎） 的问题《Exception 0x800A01B6 using getElementById after th》','https://www.manongdao.com/q-445400.html','页面编码gb2312|utf-8默认gb2312'));){kind=link}
I have created a ribbon for Powerpoint with visual studio XML ribbon. This ribbon has a button that, simplifying, does this:
- opens an IE browser
- search an element (hiddenfield) in the code by his id
- get the value of this element
- Print the value in the actual slide
It works correctly the first time I click the button of my ribbon, but it throws an Exception 0x800A01B6 the following times I click the button.
This is the code executed when I click the button:
Dim oType As Type = Type.GetTypeFromProgID("InternetExplorer.Application")
If oType IsNot Nothing Then
Dim ie As SHDocVw.InternetExplorer
ie = Nothing
ie = TryCast(Activator.CreateInstance(oType), SHDocVw.InternetExplorer)
If ie IsNot Nothing Then
Dim oEmpty As Object = [String].Empty
Dim oURL As Object = targetURL
ie.AddressBar = False
ie.MenuBar = False
ie.ToolBar = 0
ie.Visible = True
ie.Height = 800
ie.Width = 1100
ie.Navigate(oURL, oEmpty, oEmpty, oEmpty, oEmpty)
End If
Do While (ie.Busy Or ie.ReadyState <> READYSTATE.READYSTATE_COMPLETE)
Sleep(1000)
Application.DoEvents()
Loop
Sleep(10000) ' 10 seconds for testing purpose
Dim str As String = String.Empty
Dim hdnstring As HTMLInputElement = ie.Document.getElementById("hdnstring")
str = hdnstring.value
DoSomething(str)
ie.Quit()
ie = Nothing
End If
This is the code of the website that opens (targetURL), the code remains identical in every load and only the hidden value changes:
<html>
<body>
<form name="form1" id="form1">
<input type="hidden" name="hdnstring" id="hdnstring" value="Get This String" />
</form>
</body>
</html>
The second time (and following) I execute the function: the IE opens, the website fully loads, it waits 10 seconds and then I get an error in the line:
Dim hdnstring As HTMLInputElement = ie.Document.getElementById("hdnstring")
with Exception 0x800A01B6 message.
The most strange thing is that if I click viewsource in the IE contextual menu while the 10 seconds delay (the ones for testing purpose), it works perfect every time I click the button; but if I don't, the Exception 0x800A01B6 appers.
Any idea of what I'm doing wrong?
Error details image:
The type of the
Documentproperty is only resolved at run-time, so it's anObjectuntil then. This is why calling any methods in it results in the so-called late binding - you do not yet know if thegetElementByIdmethod exists or not, so that has to be determined a run-time.You most likely get the error because the
Documentis not of theIHTMLDocument3type, which is the only document type that includes thegetElementByIdmethod.What you can try is casting the
Documentto anIHTMLDocument3interface. Since it inheritsIHTMLDocumentandIHTMLDocument2you can cast between them even if the document is actually one of the earlier types.