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CListbox "Sort" property: how to change it during runtime

I have a CListbox control on a CDialog in my VC++ MFC application. In the resource editor (ie, in design time), I have the "Sort" property intentionally set to FALSE. However, I'd like to be able to change the value of the CListbox "Sort" property to TRUE while the program is running. For example, if the user clicks a button on the dialog, change the "Sort" property to TRUE.

I know I could "manaully" sort the contents of the CListbox at runtime (load them into a CString array, alphabetize them, clear the CListbox contents, and then reload the now-alphabetized contents in the CString array back into the CListbox). Tha'ts fine. I'd also just like to know how to programmatically set the "Sort" property.

Thanks very much!

jkr

That's actually pretty straightfoward, you just need to set 'LBS_SORT' via 'SetWindowLong()' (http://msdn.microsoft.com/en-us/library/windows/desktop/ms633591(v=vs.85).aspx):

HWND hwndListBox =   GetDlgItem( hDlg, ID_MY_LISTBOX ); 
DWORD dwStyle = GetWindowLong(hwndListBox , GWL_STYLE);
dwStyle = dwStyle | LBS_SORT; // enable 'sort'
SetWindowLong( hwndListBox , GWL_STYLE, dwStyle ); // apply it

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jkr

BTW, you can also disable that the same way:

HWND hwndListBox =   GetDlgItem( hDlg, ID_MY_LISTBOX ); 
DWORD dwStyle = GetWindowLong(hwndListBox , GWL_STYLE);
dwStyle = dwStyle & ~LBS_SORT; // disable 'sort'
SetWindowLong( hwndListBox , GWL_STYLE, dwStyle ); // apply it

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jkr

As a side note - you can do that also by deriving from CListBox and adding the above code as methods. Then you can obtain the window handle via 'GetSafeHwnd()' (inherited from CWnd).

jkr

To extend my lat comment, that could be like

class CMySortEnableableListBox : public CListBox
{
// other stuff...
public:

  void EnableSort()
  {
    HWND hwnd =   GetSafeHwnd();
    DWORD dwStyle = GetWindowLong(hwnd , GWL_STYLE);
    dwStyle = dwStyle | LBS_SORT; // enable 'sort'
    SetWindowLong( hwnd , GWL_STYLE, dwStyle ); // apply it                                          
  }

  void DisableSort()
  {
    HWND hwnd =   GetSafeHwnd();
    DWORD dwStyle = GetWindowLong(hwnd , GWL_STYLE);
    dwStyle = dwStyle & L+BS_SORT; // disable 'sort'
    SetWindowLong( hwnd , GWL_STYLE, dwStyle ); // apply it                                          
  }

// more stuff
};

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jkr

Do you have any further questions regarding detaild on that issue?

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sarabande

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cjm20

ASKER

thanks Sara, and thanks JKR. I tried setting the sort property as you'd described, using SetWindowLong(....). No compile errors of course, but it also did not affect the sorting in the list box. So the long way to go (two listboxes or dynamic creation / deletion of the list box) is going to be the way to go for me.

CListbox &quot;Sort&quot; property: how to change it during runtime

CListbox "Sort" property: how to change it during runtime