How to Update the List of Files in the Common Dialogs

• Microsoft Windows Software Development Kit (SDK) versions 3.1
• Microsoft Win32 Application Programming Interface (API) included with:

      - Microsoft Windows NT version 3.5
  

SUMMARY

Sometimes it is necessary to update the list of files, without terminating the dialog box, when using the File Open or Save As common dialog box. This can be done by simulating a double-click on the list box of directories. Although the message can be posted from any application, a hook procedure should be used to post the message to the dialog box window.

MORE INFORMATION

The common dialog box functions that update the list of files and directories are internal to the common dialog boxes and are not accessible by applications using the common dialog box routines. The functions are invoked and the list boxes are updated only when the user double-clicks a list box.

Sample Code

The following code uses the Cancel button of the common dialog boxes to update the list boxes:

BOOL CALLBACK __export FileOpenHook (HWND hDlg, UINT message,

                         WPARAM wParam, LPARAM lParam)
{
   switch (message)
   {
      case WM_COMMAND:
         switch(wParam)
         {
         // This simulates a double-click on the list of directories,
         // effectively forcing the common dialogs to re-read the current
         // directory of files and to refresh the list of files.
            case IDCANCEL :
               PostMessage( hDlg, WM_COMMAND, lst2,
                            MAKELPARAM(GetDlgItem(hDlg, lst2), LBN_DBLCLK);
               return TRUE;
         }
      break;
   }
   return FALSE;

If the application targets Win32, the notification message to the list box is sent differently; here is the PostMessage for Win32 applications:

PostMessage (hDlg, WM_COMMAND, MAKEWPARAM (lst2,LBN_DBLCLK),

          (LPARAM)GetDlgItem (hDlg, lst2));

The templates for the common dialog boxes are in the \SAMPLES\COMMDLG directory or in the \INCLUDE directory of the Windows SDK installation.