XL7: Code to Access MS Excel Does Not 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,
byval xTitle as long) as long

Private Declare Function SendMessageA lib "User32" (byval hwnd as long,
byval msg as long, byval wParam as long, byval lParam as long) 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
Set myExcelApp = GetObject(, "Excel.Application")
end sub 

Sample C/C++ Code

LPOLESTR   lpszProgID = OLESTR("Excel.Application");
LPUKNOWN pUnk;
HWND hExcelMainWnd =0;
hExcelMainWnd = FindWindow("XLMAIN",NULL);
if(!hExcelMainWnd)
   MessageBox(NULL,"No instances of Excel running?","Error",MB_OK);
SendMessage(hExcelMainWnd,WM_USER + 18, 0, 0);
if (FAILED(CLSIDFromProgID(lpszProgID, &clsid)))
   return;
HRESULT hr =GetActiveObject(clsid,NULL,pUnk); 

Additional query words: kbinf launched

Keywords : kbExcel
Version : WINDOWS:7.0
Platform : WINDOWS
Issue type :