Finding out if browser has been scrolled

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3 total messages Started by Brian Thu, 16 Nov 2006 22:55

#530

Author: Brian
Date: Thu, 16 Nov 2006 22:55

41 lines
2059 bytes

Hi,

I'm trying to find out if a TCppWebBrowser component has been scrolled 
vertically. I do this by finding the body tag and getting the scrollTop 
property. It works with many pages, but also fail with quite a few 
(get_scrollTop gets the value 0). What am I doing wrong? Navigating to a 
page like www.freebsd.org and scrolling it before all images have been 
loaded will cause get_scrollTop to return 0 when the downloading has 
completed.

      IHTMLDocument2 *Doc;
      if(SUCCEEDED(web->Document->QueryInterface(IID_IHTMLDocument2, 
(LPVOID*)&Doc)))
      {
        IHTMLElement *lpBodyElm = NULL;
        IHTMLElement2 *lpBody  = NULL;

        try
        {
         if( SUCCEEDED(Doc->get_body(&lpBodyElm)) )
         {
          if( 
SUCCEEDED(lpBodyElm->QueryInterface(IID_IHTMLElement2,(void**)&lpBody)) )
          {
           if( !SUCCEEDED(lpBody->get_scrollTop( &current_y)) )
           {
            // never seem to happen
           }
           lpBody->Release();
          }
          lpBodyElm->Release();
         }
        }
        catch(...)
        {
        }
     }


Thanks in advance,
Brian

Re: Finding out if browser has been scrolled

#531

Author: Remy Lebeau (TeamB)
Date: Fri, 17 Nov 2006 03:37

20 lines
1539 bytes

"Brian" <no@spam.please.com> wrote in message
news:455cec6e$1@newsgroups.borland.com...

> Navigating to a page like www.freebsd.org and scrolling it before
> all images have been loaded will cause get_scrollTop to return 0 when
> the downloading has completed.

Where exactly are you calling the code from?  Are you waiting for the
OnDocumentComplete event to trigger before doing anything?

>            if( !SUCCEEDED(lpBody->get_scrollTop( &current_y)) )
>            {
>             // never seem to happen
>            }

You are testing for "not succeeded".  Is that what you really wanted?


Gambit

Re: Finding out if browser has been scrolled

#532

Author: Brian
Date: Fri, 17 Nov 2006 08:21

28 lines
1606 bytes

Hi Remy,

> Where exactly are you calling the code from?  Are you waiting for the
> OnDocumentComplete event to trigger before doing anything?

After calling Navigate, I wait until readystate is complete:

while(web->ReadyState!=Shdocvw_tlb::READYSTATE_COMPLETE)
{
    Application->ProcessMessages();
    ::Sleep(50);
}



>>    if( !SUCCEEDED(lpBody->get_scrollTop( &current_y)) )
>>    {
>>     // never seem to happen
>>    }
> 
> You are testing for "not succeeded".  Is that what you really wanted?

Yes, it was just a test. I had a popup message there to see if 
the call to get_scrollTop failed on the pages where it returns 0. 
It doesn't.

Thanks,
Brian

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