Converting a Win32 Application to ATL

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In the midst of all this publicity writing ATL-based applications, you will
find little in the way of documentation on porting your legacy Win32 applications to
ATL. Hopefully, these steps will ease that migration path.

Migration Steps

1. Include AtlBase.h file in StdAfx.h after AfxWin.h. This is to take advantage to
   declare a variable for CComModule. Because AtlWin.h file needs, _Module as variable
   of CComModule.

   #include <atlbase.h>
   #include <objbase.h>
   

   We have to keep extern because we are originally declaring variable in
   Application main file.

   extern CComModule _Module;
   

   Then include the remaining files which helps for an ATL Application. In the insert Object of ATL uses ATLHost.h which needs to compile atlcom.h as before.

   #include <atlwin.h>
   #include <atlcom.h>
   

2. In the StdAfx.cpp, Include AtlImpl.cpp file.
3. In the main Application file, add the following

   //originally declaring the CComModule variable
   CComModule _Module;
   

   Then, Add the following two lines, which are required to activate ATL
   Object Wizard, when you choose Insert ATLObject from Insert Menu.

   BEGIN_OBJECT_MAP(ObjectMap)
   END_OBJECT_MAP()
   

4. Initialize the CComModule variable with ObjectMap and with the current
   instance in the WinMain function

   _Module.Init(ObjectMap, hInstance);
   

5. Add the <ProjectName>.idl file into the project and add the library related code:

   library TestLIB
   {
   }
   

6. If you want to insert a dialog and want to show. Follow the above steps and
   declare the variable of ur dialog class and call DoModal with that variable
   (don’t forget to include dlg header file).

Additional Notes

This code has been tested with and works fine with the Windows CE environment.

References and Acknowledgments

• ATL Internals – Rector, Sells (My thanks to the Authors!)