Auto Scrolling a Single Line PropertySheet Tab Control

Environment: all versions of windows. VC6, Win32.

When using property sheets with a large number of pages (for whatever reason) and where there is limited space available, it is often useful to use the single line version. This displays a spin control on the tab control to allow the user to scroll the various tabs into view.

The problem: When the user needs to scroll left they must continually go over to the spin control that is normally on the right hand side to scroll the tabs and then return to select the page they need.

A solution: The technique I present below gets around this problem by automatically scrolling the tabs by one when the selected tab is on the edge thus bringing the next tab into view. There may be more elegant ways to solve this but this gives you the gist.

This solution was developed primarily for use on a maximised property sheet whilst using a PocketPC, on these devices it is not possible to use the Ctrl+Tab and Ctrl+Shift+Tab keyboard shortcuts. The solution though applies equally to desktop solutions.

The PostMessage parameters were determined by using Spy++ on the
msctls_updown32 window.

HWND hTabCtrl = NULL;
HWND hWndSpin = NULL;
// Call this function whenever a propertsheet page
// receives a PSN_SETACTIVE notification:
void AutoScroll(HWND hWndMain)
{
   if(hTabCtrl)
   {
      int iItem;
      RECT rItemRect,rWindow;
      GetWindowRect(hWndMain,&rWindow);
      iItem = TabCtrl_GetCurSel(hTabCtrl);
      TabCtrl_GetItemRect(hTabCtrl,iItem,&rItemRect);
      if(rItemRect.left < 10)
      {
         PostMessage(hWndSpin,WM_LBUTTONDOWN,1,0x9000A);
         PostMessage(hWndSpin,WM_LBUTTONUP,1,0xD000D);
      }

      if(rItemRect.right > rWindow.right-40)
      {
         PostMessage(hWndSpin,WM_LBUTTONDOWN,1,0×70016);
         PostMessage(hWndSpin,WM_LBUTTONUP,1,0x6001B);
      }
   }
}
// Add this code snippet to your property sheet initialisation:
   case PSCB_INITIALIZED:
   {
      // Find the hWnd for the spin control on the tab control
      TCHAR classname[100];
      hTabCtrl = PropSheet_GetTabControl(hWndDlg);
      HWND hWndFind = GetWindow(hTabCtrl,GW_HWNDFIRST);
      while(hWndFind)
      {
         GetClassName(hWndFind,classname,100);
         if(lstrcmp(_T(“SysTabControl32”),classname) == 0)
            hWndFind = GetWindow(hWndFind,GW_CHILD);
         else if(lstrcmp(_T(“msctls_updown32”),classname) == 0)
         {
            hWndSpin = hWndFind;
            break;
         }
         else
            hWndFind = GetWindow(hWndFind,GW_HWNDNEXT);
     };
  }