WebBrowser Control--Set scroll bar position

An issue has been encountered: When you open a Web page with a WebBrowser control, the scroll bar in the Web page scrolls to the bottom.

Found a way online: Using DCOM component technology, get HTML interface pointers. (This technique is also used to do the JavaScript function in the call Web page earlier). The code is as follows:

Boolput_scrolltop ()

{

HRESULT hr;

CComPtr <idispatch > Spdisp;

IHTMLDocument2 *spdoc = NULL;

Spdisp = M_objwebbrowser.getdocument ();

hr = Spdisp->queryinterface (Iid_ihtmldocument2, (void**) &spdoc);

ASSERT (SUCCEEDED (HR));

ihtmlelement* pelement = NULL;

hr = Spdoc->get_body (&pelement);

ASSERT (SUCCEEDED (HR));

ihtmlelement2* pElement2 = NULL;

hr = Pelement->queryinterface (Iid_ihtmlelement2, (void**) &pelement2);

ASSERT (SUCCEEDED (HR));

Get the full height of scroll bars in a Web page

Long scrolltop;

Pelement2->get_scrollheight (&scrolltop);

Set the offset of the scroll bar to the top

Pelement2->put_scrolltop (scrolltop);

}

In the process of implementation, we found another problem, for a page with multiple frame, the above method is not good, so the following method is used:

Boolput_scrolltop (idispatch* pdisp)

{

HRESULT hr;

IHTMLDocument2 *spdoc = NULL;

ihtmlelementcollection* pcollection;

hr = Pdisp->queryinterface (Iid_ihtmldocument2, (void**) &spdoc);

if (FAILED (HR))

{

return false;

}

hr = Spdoc->get_all (&pcollection);

if (FAILED (HR))

{

return false;

}

Long Len;

hr = Pcollection->get_length (&len);

if (FAILED (HR))

{

return false;

}

Iterate through all the elements

For (Long l=0 l <len; l++)

{

VARIANT VarIndex, var2;

VariantInit (&varindex);

VariantInit (&VAR2);

VARINDEX.VT = VT_I4;

Varindex.lval = l;

idispatch* spdisp = NULL;

Pcollection->item (VarIndex, var2, &spdisp);

ihtmlelement* Pelem;

Spdisp->queryinterface (Iid_ihtmlelement, (lpvoid*) &pelem);

CComBSTR TagName;

Pelem->get_tagname (&tagname);

CString str = tagName;

Str. Makeupper ();

if (Str.compare (_t ("IFRAME")) = = 0 | | Str.compare (_t ("FRAME")) = = 0)

{

ihtmlelement2* pElement2 = NULL;

hr = Pelem->queryinterface (Iid_ihtmlelement2, (void**) &pelement2);

if (FAILED (HR))

{

return false;

}

Long lscrollheight;

hr = Pelement2->get_scrollheight (&lscrollheight);

if (FAILED (HR))

{

return false;

}

hr = Pelement2->put_scrolltop (lscrollheight);

if (FAILED (HR))

{

return false;

}

Pelement2->release ();

}

Pelem->release ();

Spdisp->release ();

}

Pcollection->release ();

Spdoc->release ();

return true;

}