PRB: MMC Samples/Tutorials Does Not Work on Windows 95

RESOLUTION

1. In the DllRegisterServer and DllUnregisterServer functions, change the way the string constants are declared. Use the _T("") macro to define the string constants sent the Reg* APIs. For example:

         nErr = RegOpenKey( HKEY_LOCAL_MACHINE,
                            L"Software\\Microsoft\\MMC\\SnapIns",
                            &hMmcParentKey);
   						

   Should be changed to:

         nErr = RegOpenKey( HKEY_LOCAL_MACHINE,
                            _T("Software\\Microsoft\\MMC\\SnapIns"),
                            &hMmcParentKey);
   						

   The _T("") macro will be expanded to the appropriate string constant based on the UNICODE switch.
2. In the DisplayError function, change it to accept and use LPTSTR string types.
3. Change all references to ATLTRACE to use the _T("") macro to define text constants. To find these references, use the Find In Files command from the Edit menu and then click each entry in the Find In Files list. Several of the .cpp files use this macro to display trace messages in the results window of Visual C++.
4. In the CDataObject constructor, calls are made to RegisterClipboardFormat. The standard definitions in the MMC.h file define all of the clipboard format strings in UNICODE. These strings must be converted to ASCIIZ strings when the UNICODE switch is turned off. You can use conditional compilation to insure that the strings passed to RegisterClipboardFormat are the correct type. The CDataObject::CDataObject function was changed to read as follows:

         // These are the clipboard formats that you must supply at a minimum.
         // MMC.h actually defined these. You can make up your own to use for
         // other reasons. You don't need any others at this time.
         // 
         // For ANSI, convert the format labels to ANSI if UNICODE
         // is not defined.
         // Leave them alone if they are OK.
         // 
         #ifndef UNICODE
            // 
            // If you are building an ANSI project, the
            // RegisterClipboardFormat strings must be ANSI.  From the MMC
            // headers, the strings are UNICODE and they must be converted to
            // ANSI in order to register them properly.
            // 
            // Use conditional compilation to get the job done.
            // 
            char buffer[256];
            wcstombs( buffer, CF_SNAPIN_INTERNAL,
                      wcslen(CF_SNAPIN_INTERNAL)+1);
            s_cfInternal    = RegisterClipboardFormat((LPCSTR)buffer);
            wcstombs( buffer, CCF_DISPLAY_NAME, wcslen(CCF_DISPLAY_NAME)+1);
            s_cfDisplayName = RegisterClipboardFormat((LPCSTR)buffer);
            wcstombs( buffer, CCF_NODETYPE, wcslen(CCF_NODETYPE)+1);
            s_cfNodeType    = RegisterClipboardFormat((LPCSTR)buffer);
            wcstombs( buffer, CCF_SNAPIN_CLASSID,
                      wcslen(CCF_SNAPIN_CLASSID)+1);
            s_cfSnapinClsid = RegisterClipboardFormat((LPCSTR)buffer);
         #else
            // 
            // UNICODE is defined, the clipboard formats will be OK.
   
            // 
            s_cfInternal = RegisterClipboardFormat( CF_SNAPIN_INTERNAL);
            s_cfDisplayName = RegisterClipboardFormat(CCF_DISPLAY_NAME);
            s_cfNodeType    = RegisterClipboardFormat(CCF_NODETYPE);
            s_cfSnapinClsid = RegisterClipboardFormat(CCF_SNAPIN_CLASSID);
         #endif
   						

5. As a general rule, use LPTSTR to define the strings pointers used in Win32 API calls. Use the _T("") macro for all text constants.
6. Use OLESTR inside the SnapIn. Microsoft Management Console expects UNICODE strings and will perform conversions as necessary.