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Q192883: HOWTO: Modify the VC++ COMPLEXDB Sample to Work on a Web Page

Article: Q192883
Product(s): Microsoft C Compiler
Version(s): winnt:6.0
Operating System(s): 
Keyword(s): kbtemplate kbDatabase kbInternet kbVC600 kbATL300 kbGrpDSVCDB
Last Modified: 07-MAY-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
-------------------------------------------------------------------------------

SUMMARY
=======

Visual C++, version 6.0 contains a sample called COMPLEXDB that demonstrates how
to use the Active Template Library (ATL) to write a complex data bound control.
While the control works when placed into an MFC dialog as the sample
demonstrates, additional work needs to be done to use the control from a Web
page. This article details those steps.

MORE INFORMATION
================

Perform the following steps to get the COMPLEXDB sample to work on a Web page.

1. Create a CDataSourceListener class that is derived from DataSourceListener
  (DataSourceListener is described in the ActiveX Control Writer's Kit).

2. Add the following code to the end of the ComplexCtl.cpp:

        class CDataSourceListener : public DataSourceListener
        {
           public:
             ULONG m_ulRefCount;
        CComplexCtl * m_pControl;

             CDataSourceListener(CComplexCtl * pControl):m_ulRefCount(0),
                m_pControl(pControl){}

             STDMETHOD(QueryInterface)(REFIID iid, LPVOID * ppvObject)
             {
               if (IsEqualIID(__uuidof(IUnknown), iid) ||
                   IsEqualIID(__uuidof(DataSourceListener), iid))
               {
                   *ppvObject = this;
                   AddRef();
                   return S_OK;
               }
               else
                   return E_NOINTERFACE;
             }

        STDMETHOD_(ULONG, AddRef)()
        {
               return m_ulRefCount++;
        }

             STDMETHOD_(ULONG, Release)()
             {
               if (--m_ulRefCount == 0)
               {
                  delete this;
                  return 0;
               }
               else
                  return m_ulRefCount;
        }

             STDMETHOD(dataMemberChanged)(DataMember bstrDM)
             {
               m_pControl->UpdateControl();
               return S_OK;
             };

             STDMETHOD(dataMemberAdded)(DataMember bstrDM){return S_OK;};

             STDMETHOD(dataMemberRemoved)(DataMember bstrDM){return S_OK;};

        };

3. Modify the CComplexCtl::putref_DataSource() method in CComplexCtl.cpp file to
  the following:

        STDMETHODIMP CComplexCtl::putref_DataSource(DataSource* pDataSource)
        {
           m_spDataSource = pDataSource;
           CDataSourceListener * pListener = new CDataSourceListener(this);
           // Listener object is deleted when it is released.
           m_spDataSource->addDataSourceListener(pListener);
        }

4. Create the Web page to bind the data source object to the COMPLEXDB control.
  The following example uses the RDS.DataControl control to bind data to the
  COMPLEXDB control:

       <HTML>
        <HEAD>
        <TITLE>Sample Query Page</TITLE>
        </HEAD>
        <BODY>
        <CENTER>
        <H1>Sample Query Page</H1>
        <BR>

        <OBJECT ID="COMPLEXDB" WIDTH=600 HEIGHT=200
         CLASSID="CLSID:392BBDF0-06E1-11D1-8F8F-000000000000">
           <PARAM NAME=DataSource DATASRC=#ADC>
           <PARAM NAME=FieldName  VALUE="ProductName">
        </OBJECT>

        <BR>
        <OBJECT classid="clsid:BD96C556-65A3-11D0-983A-00C04FC29E33"
         ID=ADC HEIGHT=1 WIDTH = 1>
           <PARAM NAME="Server"   VALUE="http://myIISServer">
           <PARAM NAME="Connect"     VALUE="DSN=DataTables">
           <PARAM NAME="SQL"         VALUE="Select * from Products">
        </OBJECT>
        </BODY>
        </HTML>

  NOTE: The Internet Client SDK documentation shows that you can use the
  following syntax:

        <OBJECT ID="COMPLEXDB" WIDTH=600 HEIGHT=200 Datasrc="#ADC"
          CLASSID="CLSID:392BBDF0-06E1-11D1-8F8F-000000000000">

  These lines are supposed to connect the data source object with the particular
  object. This doesn't work with Internet Explorer 4.x and OLE DB data bound
  controls. You must set the data source by using the PARAM tag shown
  previously.

REFERENCES
==========

For more information about writing OLE DB data bound controls like the COMPLEXDB
sample, see the ActiveX Control Writer's Kit included with Visual C++, version
6.0:

  Platform SDK: Database and Messaging; Microsoft Data Access SDK; OLE DB;
  ActiveX Control Writer

Additional query words:

======================================================================
Keywords          : kbtemplate kbDatabase kbInternet kbVC600 kbATL300 kbGrpDSVCDB 
Technology        : kbVCsearch kbAudDeveloper kbVC600 kbVC32bitSearch
Version           : winnt:6.0
Issue type        : kbhowto

=============================================================================

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