HOWTO: Retrieve the URL of a Web Page from an ActiveX Control

ID: Q181678

The information in this article applies to:

SUMMARY

This article demonstrates how an ActiveX control can retrieve the Uniform Resource Locator (URL) of the Web page (document) on which it is being hosted.

This may be useful for restricting usage of an ActiveX control to a particular domain/site or accessing files when supplied a relative path.


MORE INFORMATION

During the initialization of an embedded ActiveX control, Internet Explorer (IE) passes a pointer to its client site by calling IOleObject::SetClientSite(). This process can be used to either retrieve a moniker for the container or access the document object model to retrieve the URL for the hosting Web page.

This article demonstrates how to retrieve the current URL from the container moniker. For additional information about how to obtain the URL from the document object model, please see the following article in the Microsoft Knowledge Base:

Q172763 INFO: Accessing the Object Model from Within an ActiveX Control
Follow these steps to retrieve the current URL from the container moniker:
  1. Obtain the client site (IOleClientSite) interface pointer. The container calls IOleObject::SetClientSite() to pass a pointer to the client site. Override this method to cache this pointer.


  2. Obtain a moniker to the client site by calling IOleClientSite::GetMoniker().


  3. Call IMoniker::GetDisplayName() to obtain the URL for the current document.


The following sample code demonstrates how to perform the above steps by overriding the IOleObject::SetClientSite() method in an Active Template Library (ATL) ActiveX control:

Sample Code


STDMETHOD(SetClientSite)(IOleClientSite *pClientSite)
{
   if (pClientSite != NULL)
   {
      // Obtain URL from container moniker.
      CComPtr<IMoniker> spmk;
      LPOLESTR pszDisplayName;

      if (SUCCEEDED(pClientSite->GetMoniker(
                                    OLEGETMONIKER_TEMPFORUSER,
                                    OLEWHICHMK_CONTAINER,
                                    &spmk)))
      {
         if (SUCCEEDED(spmk->GetDisplayName(
                                 NULL, NULL, &pszDisplayName)))
         {
            USES_CONVERSION;

            CComBSTR bstrURL;
            bstrURL = pszDisplayName;

            ATLTRACE("The current URL is %s\n", OLE2T(bstrURL));
            CoTaskMemFree((LPVOID)pszDisplayName);
         }
      }
   }

   return IOleObject_SetClientSite(pClientSite);
}


REFERENCES

For more information on the IOleObject, IoleClientSite, and IOleContainer interfaces, please refer to the Microsoft Visual C++ online help.

(c) Microsoft Corporation 1998, All Rights Reserved. Contributions by Mark Davis, Microsoft Corporation

Additional query words: 


Keywords          : kbIE300 kbIE400 kbIE401 kbIE500 AXSDKControls 
Version           : WINDOWS:1.0,3.0,3.01,3.02,4.0,4.01
Platform          : WINDOWS 
Issue type        : kbhowto

Last Reviewed: April 27, 1999