Article ID: 138723
Article Last Modified on 8/17/2005
APPLIES TO
- Microsoft Excel 95 Standard Edition
This article was previously published under Q138723
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);
This code will not work with Microsoft Excel version 7.0, even if Microsoft Excel is running.
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.
The following VB 4.0 and C/C++ code samples show how to use the WM_USER+18 option to get an OLE Automation object from an already running instance of 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: kbnoupdate KB138723
