A couple days ago I showed you how to access the Microsoft Word 2007 COM API through Microsoft Active Accessibility (MSAA). Today, I’m going to switch it up just a little bit, and use the same method to access the Microsoft Excel 2007 COM API. Again, we’ll be using AccesssibleObjectFromWindow to get at the main Excel::Window object. From that object, you can obtain the Excel Application, and Excel Workbook objects. Some documentation from Microsoft can be found here.

First we obtain the hwnd of the Microsoft Excel Process:

//The main window in Microsoft Excel has a class name of XLMAIN
HWND excelWindow = FindWindow(L"XLMAIN", NULL);

We can then traverse the child windows until we find the one with classname EXCEL7:

//Use the EnumChildWindows function to iterate through all child windows until we find EXCEL7
EnumChildWindows(excelWindow, (WNDENUMPROC) EnumChildProc, (LPARAM)1);

static BOOL EnumChildProc(HWND hwnd, LPARAM)
{
     WCHAR szClassName[64];
     if(GetClassNameW(hwnd, szClassName, 64))
     {
          if(_wcsicmp(szClassName, L"EXCEL7") == 0)
          {
               //Get AccessibleObject
               Excel::Window* pWindow = NULL;
               HRESULT hr = AccessibleObjectFromWindow(hwnd, OBJID_NATIVEOM, __uuidof(Excel::Window), (void**)&pWindow);
               if(hr == S_OK)
               {
                    //Excel object is now in pWindow pointer, from this you can obtain the document or application
                    Excel::_Application* pApp = NULL;
                    pWindow->get_Application(&pApp);
                    pWindow->Release();
               }
               return false;     // Stops enumerating through children
          }
     }
     return true;
}

Next we obtain our Excel::Window object through AccessibleObjectFromWindow:

//Get AccessibleObject
Excel::Window* pWindow = NULL;
HRESULT hr = AccessibleObjectFromWindow(hwnd, OBJID_NATIVEOM, __uuidof(Excel::Window), (void**)&pWindow);

That’s it! We now have our Excel::Window COM Object. From this object we can obtain the Excel::Application and Excel::Workbook objects, allowing us full interaction with the active document. So with just a few lines of code, we now have access to automate an Excel 2007 document.

Full source code:

#include <windows.h>
#include <oleacc.h>
#include "msexcel.h"

static BOOL EnumChildProc(HWND hwnd, LPARAM)
{
     WCHAR szClassName[64];
     if(GetClassNameW(hwnd, szClassName, 64))
     {
          if(_wcsicmp(szClassName, L"EXCEL7") == 0)
          {
               //Get AccessibleObject
               Excel::Window* pWindow = NULL;
               HRESULT hr = AccessibleObjectFromWindow(hwnd, OBJID_NATIVEOM, __uuidof(Excel::Window), (void**)&pWindow);
               if(hr == S_OK)
               {
                    //Excel object is now in pWindow pointer, from this you can obtain the document or application
                    Excel::_Application* pApp = NULL;
                    pWindow->get_Application(&pApp);
                    pWindow->Release();
               }
               return false;     // Stops enumerating through children
          }
     }
	 return true;
}
int main( int argc, CHAR* argv[])
{
     //The main window in Microsoft Excel has a class name of XLMAIN
     HWND excelWindow = FindWindow(L"XLMAIN", NULL);

     //Use the EnumChildWindows function to iterate through all child windows until we find _WwG
     EnumChildWindows(excelWindow, (WNDENUMPROC) EnumChildProc, (LPARAM)1);

     return 0;
}

Useful Links for this post:

• AccessibleObjectFromWindow Documentation
• Using Visual C++ to Automate Office
• EnumChildWindows Documentation

Key phrases: Accessing Excel 2007 COM object using AccessibleObjectFromWindow, Automating Excel 2007 with Microsoft Active Accessibility MSAA
Update: I’ve updated the full source to utilize get_Application. get_Document was in place previously, which was leftover from my Word source code.