XL7: Code to Access MS Excel Doesn't Work in Version 7.0

• Microsoft Excel for Windows 95, version 7.0

SYMPTOMS

In earlier versions of Microsoft Excel, you can create Visual Basic or C/C++ code to allow another application to access a currently running instance of Microsoft Excel. To do this, you use code similar to the code in the following examples:

   VB Code Example
   ---------------

   Dim myExcelApp As Object
   Set myExcelApp = GetObject(, "Excel.Application")

   C/C++ Code Example
   ------------------

   LPOLESTR   lpszProgID = OLESTR("Excel.Application");
   LPUNKNOWN pUnk;
   if (FAILED(CLSIDFromProgID(lpszProgID, &clsid)))
      return;
   HRESULT hr =GetActiveObject(clsid,NULL,pUnk);

CAUSE

Earlier versions of Microsoft Excel register the application object in the OLE RunningObjectTable (ROT) on startup. This registration occurs under all circumstances, regardless of whether Microsoft Excel is started by OLE. However, Microsoft Excel 7.0 does not register the application object in the ROT on startup by default.

STATUS

This change in Microsoft Excel 7.0 is by design.

MORE INFORMATION

Microsoft Excel 7.0 DOES register itself in the ROT in the following situations:

• When it's started by OLE; that is, when a client calls CoCreateInstance(), CoGetClassObject(), or CreateInstance().
• When a module is inserted in one of the workbooks.
• When a WM_USER+18 message is sent to the Main window of Microsoft Excel.

Sample VB Code

Private Declare Function FindWindowA lib "User32" (byval sClass as String,

Private Declare Function SendMessageA lib "User32" (byval hwnd as long,

Private const WM_USER = 1024 Dim myExcelApp As Object

sub KickExcel()
   dim hwnd as long

   hwnd = FindWindowA("XLMAIN", 0)
   if hwnd = 0 then
      msgbox "No instances of Excel running?"
      exit sub
   endif
   SendMessageA hwnd, WM_USER + 18, 0, 0

Sample C/C++ Code

LPOLESTR   lpszProgID = OLESTR("Excel.Application");

   MessageBox(NULL,"No instances of Excel running?","Error",MB_OK);

   return;