PRB: Common Controls Might Behave Unpredictably in an Interactive Service after Logoff (238721)

MORE INFORMATION

An interactive service is a service that interacts with the currently logged-on user through a typical Windows-based user interface.

The common controls library contains many enhanced Windows controls, like the List View, Tree View, and ComboBoxEx controls.

An atom table is a system-defined table that stores strings and corresponding identifiers. An application places a string in an atom table and receives a 16-bit integer, named an atom, which can be used to access the string from any thread within the same desktop.

A desktop is a kernel object contained within a window station object. A desktop has a logical display surface and contains windows, menus, hooks, and a global atom table. This atom table can be used to uniquely identify data that is shared among other threads running in the same desktop.

For additional information about the interactive desktop, click the article number below to view the article in the Microsoft Knowledge Base:

Problems Using Microsoft Foundation Class Library Within Services

The Microsoft Foundation Class (MFC) library loads and initializes the Comctl32.dll file when an MFC dialog is initialized; this occurs even when no common control is used within the dialog. In addition, the MFC library itself uses global atoms to store data for subclassing windows. For these reasons, you should not use MFC within a service. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

Sample Code

The following sample code implements a useful function, CCDialogBox, which you can use to create a dialog box that contains common controls. The CCDialogBox function dynamically loads and initializes the common controls library. When the dialog box closes, the library is unloaded.

The first four parameters for the CCDialogBox function are identical to the parameters passed to the DialogBox function. The last parameter, dwICC, should contain the bit flags that indicate which common control classes to load. For the possible flag values, see the online documentation for the INITCOMMONCONTROLSEX structure.

Here is the sample code:

#include <Windows.h>
#include <CommCtrl.h>

typedef BOOL (STDMETHODCALLTYPE FAR * LPFNINITCOMCTL32) (
      LPINITCOMMONCONTROLSEX lpInitCtrls
);

INT_PTR CCDialogBox(
      HINSTANCE hInstance,    // handle to module
      LPCTSTR   lpTemplate,   // dialog box template
      HWND      hWndParent,   // handle to owner window
      DLGPROC   lpDialogFunc, // dialog box procedure
      DWORD     dwICC ) {     // bit flags for common control classes
                              // to load

   HMODULE hComCtl32 = NULL;
   INT_PTR iResult   = -1;

   __try {

      INITCOMMONCONTROLSEX icce;
      LPFNINITCOMCTL32     InitComCtl32;

      hComCtl32 = LoadLibrary("comctl32.dll");
      if (!hComCtl32)
         __leave;

      InitComCtl32 = (LPFNINITCOMCTL32) GetProcAddress(hComCtl32, 
            "InitCommonControlsEx");
      if (!InitComCtl32)
         __leave;

      icce.dwSize = sizeof(icce);
      icce.dwICC  = dwICC;
      InitComCtl32(&icce);

      iResult = DialogBox(hInstance, lpTemplate, hWndParent, lpDialogFunc);

   } __finally {

      if (hComCtl32)
         FreeLibrary(hComCtl32);
   }

   return iResult;
}