HOWTO: Connecting to a Running Instance of Internet Explorer

• Microsoft Internet Explorer (Programming), versions 4.0, 4.01
• Internet Client SDK, version 4.0, 4.01

SUMMARY

It is possible to connect to a running instance of Internet Explorer 4.0 (IE4) using the SHDocVw.ShellWindows collection.

MORE INFORMATION

Normally, an application connects to a running instance of another application using the Running Object table. Because Internet Explorer 4.0 does not register itself in the running object table, another method is necessary.

The ShellWindows collection is described in the Internet Client SDK as follows: The ShellWindows object represents a collection of the open windows that belong to the shell. In fact, this collection contains references to Internet Explorer as well as other windows belonging to the shell, such as the Windows Explorer.

The following Visual Basic code obtains a reference to the ShellWindows collection. The collection is enumerated and the LocationName for each object added to a list box. If the document associated with the object is of type HTMLDocument (a Web Page), the title for the page is added to another list box.

In order to run the following code, it is necessary to add a reference to Shdocvw.dll and Mshtml.dll to the Visual Basic project:

   Dim SWs As New SHDocVw.ShellWindows
   Dim IE As SHDocVw.InternetExplorer

   Private Sub Form_Load()
      Dim Doc
      List1.Clear
      List2.Clear

      Text1.Text = SWs.count

      For Each IE In SWs
         List1.AddItem IE.LocationName

         Set Doc = IE.Document
         If TypeOf Doc Is HTMLDocument Then
            'if this is an HTML page, display the title
            'may or may not be the same as LocationName
            List2.AddItem Doc.Title
         End If
      Next
   End Sub

Add references to Shdocvw.dll and Mshtml.dll to the project:

   #import "mshtml.dll"
   #import "shdocvw.dll" exclude("tagREADYSTATE")

   SHDocVw::IShellWindowsPtr m_spSHWinds;

   m_spSHWinds.CreateInstance(__uuidof(SHDocVw::ShellWindows));

   void CConnectIEView::OnInitialUpdate()
   {
      CFormView::OnInitialUpdate();

      ASSERT(m_spSHWinds != NULL);

      CString strCount;
      long nCount = m_spSHWinds->GetCount();

      strCount.Format("%i", nCount);
      m_strWinCount = strCount;

      UpdateData(FALSE);

      IDispatchPtr spDisp;
      for (long i = 0; i < nCount; i++)
      {
         _variant_t va(i, VT_I4);
         spDisp = m_spSHWinds->Item(va);

         SHDocVw::IWebBrowser2Ptr spBrowser(spDisp);
         if (spBrowser != NULL)
         {
            m_ctlListLoc.AddString(spBrowser->GetLocationName());

            MSHTML::IHTMLDocument2Ptr spDoc(spBrowser->GetDocument());
            if (spDoc != NULL)
            {
                m_ctlListTitle.AddString(spDoc->Gettitle());
            }
         }
      }
   }

If these factors cannot be controlled, there is still one possible method that may work. A browser helper object can be written to register Internet Explorer 4.0 in the running object table (ROT). There are many implementations possible here depending on how the application is to determine the instance of Internet Explorer with which to connect. This is just one possible solution: The browser helper object, having access to the object model of the instance of Explorer that launched it, would determine if this is the instance of the browser that should be registered in the running object table.

The interface that the consumer is interested in can be registered in the ROT with the RegisterActiveObject function and a dummy CLSID that the consumer will recognize. Another solution, that would allow multiple instances of the explorer to be registered in the ROT, would be to have the Browser Helper object compose an Item moniker based on a GUID and piece of data unique to each instance of Internet Explorer. The moniker would be registered in the ROT with the IRunningObjectTable::Register method. Again, the consumer would have to know how recognize this moniker.

REFERENCES

The Internet Client SDK; search on Internet Tools and Technologies - Windows Shell API

For additional information, please see the following article(s) in the Microsoft Knowledge Base:

   ARTICLE-ID: Q179230
   TITLE : FILE: IEHelper-Attaching to IE4 using a Browser Helper Object