src/msw/listbox.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/listbox.cpp
   3 // Purpose:     wxListBox
   4 // Author:      Julian Smart
   5 // Modified by: Vadim Zeitlin (owner drawn stuff)
   6 // Created:
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 // For compilers that support precompilation, includes "wx.h".
  13 #include "wx/wxprec.h"
  14
  15 #ifdef __BORLANDC__
  16     #pragma hdrstop
  17 #endif
  18
  19 #if wxUSE_LISTBOX
  20
  21 #include "wx/listbox.h"
  22
  23 #ifndef WX_PRECOMP
  24     #include "wx/dynarray.h"
  25     #include "wx/settings.h"
  26     #include "wx/brush.h"
  27     #include "wx/font.h"
  28     #include "wx/dc.h"
  29     #include "wx/utils.h"
  30     #include "wx/log.h"
  31     #include "wx/window.h"
  32 #endif
  33
  34 #include "wx/msw/private.h"
  35 #include "wx/msw/dc.h"
  36
  37 #include <windowsx.h>
  38
  39 #if wxUSE_OWNER_DRAWN
  40     #include  "wx/ownerdrw.h"
  41 #endif
  42
  43 // ============================================================================
  44 // list box item declaration and implementation
  45 // ============================================================================
  46
  47 #if wxUSE_OWNER_DRAWN
  48
  49 class wxListBoxItem : public wxOwnerDrawn
  50 {
  51 public:
  52     wxListBoxItem(wxListBox *parent)
  53         { m_parent = parent; }
  54
  55     wxListBox *GetParent() const
  56         { return m_parent; }
  57
  58     int GetIndex() const
  59         { return m_parent->GetItemIndex(const_cast<wxListBoxItem*>(this)); }
  60
  61     wxString GetName() const
  62         { return m_parent->GetString(GetIndex()); }
  63
  64 private:
  65     wxListBox *m_parent;
  66 };
  67
  68 wxOwnerDrawn *wxListBox::CreateLboxItem(size_t WXUNUSED(n))
  69 {
  70     return new wxListBoxItem(this);
  71 }
  72
  73 #endif  //USE_OWNER_DRAWN
  74
  75 // ============================================================================
  76 // list box control implementation
  77 // ============================================================================
  78
  79 // ----------------------------------------------------------------------------
  80 // creation
  81 // ----------------------------------------------------------------------------
  82
  83 void wxListBox::Init()
  84 {
  85     m_noItems = 0;
  86     m_updateHorizontalExtent = false;
  87     m_selectedByKeyboard = false;
  88 }
  89
  90 bool wxListBox::Create(wxWindow *parent,
  91                        wxWindowID id,
  92                        const wxPoint& pos,
  93                        const wxSize& size,
  94                        int n, const wxString choices[],
  95                        long style,
  96                        const wxValidator& validator,
  97                        const wxString& name)
  98 {
  99     // initialize base class fields
 100     if ( !CreateControl(parent, id, pos, size, style, validator, name) )
 101         return false;
 102
 103     // create the native control
 104     if ( !MSWCreateControl(wxT("LISTBOX"), wxEmptyString, pos, size) )
 105     {
 106         // control creation failed
 107         return false;
 108     }
 109
 110     // initialize the contents
 111     for ( int i = 0; i < n; i++ )
 112     {
 113         Append(choices[i]);
 114     }
 115
 116     // now we can compute our best size correctly, so do it again
 117     SetInitialSize(size);
 118
 119     return true;
 120 }
 121
 122 bool wxListBox::Create(wxWindow *parent,
 123                        wxWindowID id,
 124                        const wxPoint& pos,
 125                        const wxSize& size,
 126                        const wxArrayString& choices,
 127                        long style,
 128                        const wxValidator& validator,
 129                        const wxString& name)
 130 {
 131     wxCArrayString chs(choices);
 132     return Create(parent, id, pos, size, chs.GetCount(), chs.GetStrings(),
 133                   style, validator, name);
 134 }
 135
 136 wxListBox::~wxListBox()
 137 {
 138     Clear();
 139 }
 140
 141 WXDWORD wxListBox::MSWGetStyle(long style, WXDWORD *exstyle) const
 142 {
 143     WXDWORD msStyle = wxControl::MSWGetStyle(style, exstyle);
 144
 145     // we always want to get the notifications
 146     msStyle |= LBS_NOTIFY;
 147
 148     // without this style, you get unexpected heights, so e.g. constraint
 149     // layout doesn't work properly
 150     msStyle |= LBS_NOINTEGRALHEIGHT;
 151
 152     wxASSERT_MSG( !(style & wxLB_MULTIPLE) || !(style & wxLB_EXTENDED),
 153                   wxT("only one of listbox selection modes can be specified") );
 154
 155     if ( style & wxLB_MULTIPLE )
 156         msStyle |= LBS_MULTIPLESEL;
 157     else if ( style & wxLB_EXTENDED )
 158         msStyle |= LBS_EXTENDEDSEL;
 159
 160     wxASSERT_MSG( !(style & wxLB_ALWAYS_SB) || !(style & wxLB_NO_SB),
 161                   wxT( "Conflicting styles wxLB_ALWAYS_SB and wxLB_NO_SB." ) );
 162
 163     if ( !(style & wxLB_NO_SB) )
 164     {
 165         msStyle |= WS_VSCROLL;
 166         if ( style & wxLB_ALWAYS_SB )
 167             msStyle |= LBS_DISABLENOSCROLL;
 168     }
 169
 170     if ( m_windowStyle & wxLB_HSCROLL )
 171         msStyle |= WS_HSCROLL;
 172     if ( m_windowStyle & wxLB_SORT )
 173         msStyle |= LBS_SORT;
 174
 175 #if wxUSE_OWNER_DRAWN && !defined(__WXWINCE__)
 176     if ( m_windowStyle & wxLB_OWNERDRAW )
 177     {
 178         // we don't support LBS_OWNERDRAWVARIABLE yet and we also always put
 179         // the strings in the listbox for simplicity even though we could have
 180         // avoided it in this case
 181         msStyle |= LBS_OWNERDRAWFIXED | LBS_HASSTRINGS;
 182     }
 183 #endif // wxUSE_OWNER_DRAWN
 184
 185     return msStyle;
 186 }
 187
 188 void wxListBox::OnInternalIdle()
 189 {
 190     wxWindow::OnInternalIdle();
 191
 192     if (m_updateHorizontalExtent)
 193     {
 194         SetHorizontalExtent(wxEmptyString);
 195         m_updateHorizontalExtent = false;
 196     }
 197 }
 198
 199 void wxListBox::MSWOnItemsChanged()
 200 {
 201     // we need to do two things when items change: update their max horizontal
 202     // extent so that horizontal scrollbar could be shown or hidden as
 203     // appropriate and also invlaidate the best size
 204     //
 205     // updating the max extent is slow (it's an O(N) operation) and so we defer
 206     // it until the idle time but the best size should be invalidated
 207     // immediately doing it in idle time is too late -- layout using incorrect
 208     // old best size will have been already done by then
 209
 210     m_updateHorizontalExtent = true;
 211
 212     InvalidateBestSize();
 213 }
 214
 215 // ----------------------------------------------------------------------------
 216 // implementation of wxListBoxBase methods
 217 // ----------------------------------------------------------------------------
 218
 219 void wxListBox::DoSetFirstItem(int N)
 220 {
 221     wxCHECK_RET( IsValid(N),
 222                  wxT("invalid index in wxListBox::SetFirstItem") );
 223
 224     SendMessage(GetHwnd(), LB_SETTOPINDEX, (WPARAM)N, (LPARAM)0);
 225 }
 226
 227 void wxListBox::DoDeleteOneItem(unsigned int n)
 228 {
 229     wxCHECK_RET( IsValid(n),
 230                  wxT("invalid index in wxListBox::Delete") );
 231
 232 #if wxUSE_OWNER_DRAWN
 233     if ( HasFlag(wxLB_OWNERDRAW) )
 234     {
 235         delete m_aItems[n];
 236         m_aItems.RemoveAt(n);
 237     }
 238 #endif // wxUSE_OWNER_DRAWN
 239
 240     SendMessage(GetHwnd(), LB_DELETESTRING, n, 0);
 241     m_noItems--;
 242
 243     MSWOnItemsChanged();
 244
 245     UpdateOldSelections();
 246 }
 247
 248 int wxListBox::FindString(const wxString& s, bool bCase) const
 249 {
 250     // back to base class search for not native search type
 251     if (bCase)
 252        return wxItemContainerImmutable::FindString( s, bCase );
 253
 254     int pos = ListBox_FindStringExact(GetHwnd(), -1, s.wx_str());
 255     if (pos == LB_ERR)
 256         return wxNOT_FOUND;
 257     else
 258         return pos;
 259 }
 260
 261 void wxListBox::DoClear()
 262 {
 263 #if wxUSE_OWNER_DRAWN
 264     if ( HasFlag(wxLB_OWNERDRAW) )
 265     {
 266         WX_CLEAR_ARRAY(m_aItems);
 267     }
 268 #endif // wxUSE_OWNER_DRAWN
 269
 270     ListBox_ResetContent(GetHwnd());
 271
 272     m_noItems = 0;
 273     MSWOnItemsChanged();
 274
 275     UpdateOldSelections();
 276 }
 277
 278 void wxListBox::DoSetSelection(int N, bool select)
 279 {
 280     wxCHECK_RET( N == wxNOT_FOUND || IsValid(N),
 281                  wxT("invalid index in wxListBox::SetSelection") );
 282
 283     if ( HasMultipleSelection() )
 284     {
 285         // Setting selection to -1 should deselect everything.
 286         const bool deselectAll = N == wxNOT_FOUND;
 287         SendMessage(GetHwnd(), LB_SETSEL,
 288                     deselectAll ? FALSE : select,
 289                     deselectAll ? -1 : N);
 290     }
 291     else
 292     {
 293         SendMessage(GetHwnd(), LB_SETCURSEL, select ? N : -1, 0);
 294     }
 295
 296     UpdateOldSelections();
 297 }
 298
 299 bool wxListBox::IsSelected(int N) const
 300 {
 301     wxCHECK_MSG( IsValid(N), false,
 302                  wxT("invalid index in wxListBox::Selected") );
 303
 304     return SendMessage(GetHwnd(), LB_GETSEL, N, 0) == 0 ? false : true;
 305 }
 306
 307 void *wxListBox::DoGetItemClientData(unsigned int n) const
 308 {
 309     return (void *)SendMessage(GetHwnd(), LB_GETITEMDATA, n, 0);
 310 }
 311
 312 void wxListBox::DoSetItemClientData(unsigned int n, void *clientData)
 313 {
 314     if ( ListBox_SetItemData(GetHwnd(), n, clientData) == LB_ERR )
 315     {
 316         wxLogDebug(wxT("LB_SETITEMDATA failed"));
 317     }
 318 }
 319
 320 // Return number of selections and an array of selected integers
 321 int wxListBox::GetSelections(wxArrayInt& aSelections) const
 322 {
 323     aSelections.Empty();
 324
 325     if ( HasMultipleSelection() )
 326     {
 327         int countSel = ListBox_GetSelCount(GetHwnd());
 328         if ( countSel == LB_ERR )
 329         {
 330             wxLogDebug(wxT("ListBox_GetSelCount failed"));
 331         }
 332         else if ( countSel != 0 )
 333         {
 334             int *selections = new int[countSel];
 335
 336             if ( ListBox_GetSelItems(GetHwnd(),
 337                                      countSel, selections) == LB_ERR )
 338             {
 339                 wxLogDebug(wxT("ListBox_GetSelItems failed"));
 340                 countSel = -1;
 341             }
 342             else
 343             {
 344                 aSelections.Alloc(countSel);
 345                 for ( int n = 0; n < countSel; n++ )
 346                     aSelections.Add(selections[n]);
 347             }
 348
 349             delete [] selections;
 350         }
 351
 352         return countSel;
 353     }
 354     else  // single-selection listbox
 355     {
 356         if (ListBox_GetCurSel(GetHwnd()) > -1)
 357             aSelections.Add(ListBox_GetCurSel(GetHwnd()));
 358
 359         return aSelections.Count();
 360     }
 361 }
 362
 363 // Get single selection, for single choice list items
 364 int wxListBox::GetSelection() const
 365 {
 366     wxCHECK_MSG( !HasMultipleSelection(),
 367                  -1,
 368                  wxT("GetSelection() can't be used with multiple-selection listboxes, use GetSelections() instead.") );
 369
 370     return ListBox_GetCurSel(GetHwnd());
 371 }
 372
 373 // Find string for position
 374 wxString wxListBox::GetString(unsigned int n) const
 375 {
 376     wxCHECK_MSG( IsValid(n), wxEmptyString,
 377                  wxT("invalid index in wxListBox::GetString") );
 378
 379     int len = ListBox_GetTextLen(GetHwnd(), n);
 380
 381     // +1 for terminating NUL
 382     wxString result;
 383     ListBox_GetText(GetHwnd(), n, (wxChar*)wxStringBuffer(result, len + 1));
 384
 385     return result;
 386 }
 387
 388 int wxListBox::DoInsertItems(const wxArrayStringsAdapter & items,
 389                              unsigned int pos,
 390                              void **clientData,
 391                              wxClientDataType type)
 392 {
 393     MSWAllocStorage(items, LB_INITSTORAGE);
 394
 395     const bool append = pos == GetCount();
 396
 397     // we must use CB_ADDSTRING when appending as only it works correctly for
 398     // the sorted controls
 399     const unsigned msg = append ? LB_ADDSTRING : LB_INSERTSTRING;
 400
 401     if ( append )
 402         pos = 0;
 403
 404     int n = wxNOT_FOUND;
 405
 406     const unsigned int numItems = items.GetCount();
 407     for ( unsigned int i = 0; i < numItems; i++ )
 408     {
 409         n = MSWInsertOrAppendItem(pos, items[i], msg);
 410         if ( n == wxNOT_FOUND )
 411             return n;
 412
 413         if ( !append )
 414             pos++;
 415
 416         ++m_noItems;
 417
 418 #if wxUSE_OWNER_DRAWN
 419         if ( HasFlag(wxLB_OWNERDRAW) )
 420         {
 421             wxOwnerDrawn *pNewItem = CreateLboxItem(n);
 422             pNewItem->SetFont(GetFont());
 423             m_aItems.Insert(pNewItem, n);
 424         }
 425 #endif // wxUSE_OWNER_DRAWN
 426         AssignNewItemClientData(n, clientData, i, type);
 427     }
 428
 429     MSWOnItemsChanged();
 430
 431     UpdateOldSelections();
 432
 433     return n;
 434 }
 435
 436 int wxListBox::DoHitTestList(const wxPoint& point) const
 437 {
 438     LRESULT lRes = ::SendMessage(GetHwnd(), LB_ITEMFROMPOINT,
 439                                  0, MAKELPARAM(point.x, point.y));
 440
 441     // non zero high-order word means that this item is outside of the client
 442     // area, IOW the point is outside of the listbox
 443     return HIWORD(lRes) ? wxNOT_FOUND : LOWORD(lRes);
 444 }
 445
 446 void wxListBox::SetString(unsigned int n, const wxString& s)
 447 {
 448     wxCHECK_RET( IsValid(n),
 449                  wxT("invalid index in wxListBox::SetString") );
 450
 451     // remember the state of the item
 452     bool wasSelected = IsSelected(n);
 453
 454     void *oldData = NULL;
 455     wxClientData *oldObjData = NULL;
 456     if ( HasClientUntypedData() )
 457         oldData = GetClientData(n);
 458     else if ( HasClientObjectData() )
 459         oldObjData = GetClientObject(n);
 460
 461     // delete and recreate it
 462     SendMessage(GetHwnd(), LB_DELETESTRING, n, 0);
 463
 464     int newN = n;
 465     if ( n == (m_noItems - 1) )
 466         newN = -1;
 467
 468     ListBox_InsertString(GetHwnd(), newN, s.wx_str());
 469
 470     // restore the client data
 471     if ( oldData )
 472         SetClientData(n, oldData);
 473     else if ( oldObjData )
 474         SetClientObject(n, oldObjData);
 475
 476     // we may have lost the selection
 477     if ( wasSelected )
 478         Select(n);
 479
 480     MSWOnItemsChanged();
 481 }
 482
 483 unsigned int wxListBox::GetCount() const
 484 {
 485     return m_noItems;
 486 }
 487
 488 // ----------------------------------------------------------------------------
 489 // size-related stuff
 490 // ----------------------------------------------------------------------------
 491
 492 void wxListBox::SetHorizontalExtent(const wxString& s)
 493 {
 494     // the rest is only necessary if we want a horizontal scrollbar
 495     if ( !HasFlag(wxHSCROLL) )
 496         return;
 497
 498
 499     WindowHDC dc(GetHwnd());
 500     SelectInHDC selFont(dc, GetHfontOf(GetFont()));
 501
 502     TEXTMETRIC lpTextMetric;
 503     ::GetTextMetrics(dc, &lpTextMetric);
 504
 505     int largestExtent = 0;
 506     SIZE extentXY;
 507
 508     if ( s.empty() )
 509     {
 510         // set extent to the max length of all strings
 511         for ( unsigned int i = 0; i < m_noItems; i++ )
 512         {
 513             const wxString str = GetString(i);
 514             ::GetTextExtentPoint32(dc, str.c_str(), str.length(), &extentXY);
 515
 516             int extentX = (int)(extentXY.cx + lpTextMetric.tmAveCharWidth);
 517             if ( extentX > largestExtent )
 518                 largestExtent = extentX;
 519         }
 520     }
 521     else // just increase the extent to the length of this string
 522     {
 523         int existingExtent = (int)SendMessage(GetHwnd(),
 524                                               LB_GETHORIZONTALEXTENT, 0, 0L);
 525
 526         ::GetTextExtentPoint32(dc, s.c_str(), s.length(), &extentXY);
 527
 528         int extentX = (int)(extentXY.cx + lpTextMetric.tmAveCharWidth);
 529         if ( extentX > existingExtent )
 530             largestExtent = extentX;
 531     }
 532
 533     if ( largestExtent )
 534         SendMessage(GetHwnd(), LB_SETHORIZONTALEXTENT, LOWORD(largestExtent), 0L);
 535     //else: it shouldn't change
 536 }
 537
 538 wxSize wxListBox::DoGetBestClientSize() const
 539 {
 540     // find the widest string
 541     int wLine;
 542     int wListbox = 0;
 543     for (unsigned int i = 0; i < m_noItems; i++)
 544     {
 545         wxString str(GetString(i));
 546         GetTextExtent(str, &wLine, NULL);
 547         if ( wLine > wListbox )
 548             wListbox = wLine;
 549     }
 550
 551     // give it some reasonable default value if there are no strings in the
 552     // list
 553     if ( wListbox == 0 )
 554         wListbox = 100;
 555
 556     // the listbox should be slightly larger than the widest string
 557     wListbox += 3*GetCharWidth();
 558
 559     // add room for the scrollbar
 560     wListbox += wxSystemSettings::GetMetric(wxSYS_VSCROLL_X);
 561
 562     // don't make the listbox too tall (limit height to 10 items) but don't
 563     // make it too small neither
 564     int hListbox = SendMessage(GetHwnd(), LB_GETITEMHEIGHT, 0, 0)*
 565                     wxMin(wxMax(m_noItems, 3), 10);
 566
 567     return wxSize(wListbox, hListbox);
 568 }
 569
 570 // ----------------------------------------------------------------------------
 571 // callbacks
 572 // ----------------------------------------------------------------------------
 573
 574 bool wxListBox::MSWCommand(WXUINT param, WXWORD WXUNUSED(id))
 575 {
 576     wxEventType evtType;
 577     int n = wxNOT_FOUND;
 578     if ( param == LBN_SELCHANGE )
 579     {
 580         if ( HasMultipleSelection() )
 581             return CalcAndSendEvent();
 582
 583         evtType = wxEVT_COMMAND_LISTBOX_SELECTED;
 584
 585         if ( m_selectedByKeyboard )
 586         {
 587             // We shouldn't use the mouse position to find the item as mouse
 588             // can be anywhere, ask the listbox itself. Notice that this can't
 589             // be used when the item is selected using the mouse however as
 590             // LB_GETCARETINDEX will always return a valid item, even if the
 591             // mouse is clicked below all the items, which is why we find the
 592             // item ourselves below in this case.
 593             n = SendMessage(GetHwnd(), LB_GETCARETINDEX, 0, 0);
 594         }
 595         //else: n will be determined below from the mouse position
 596     }
 597     else if ( param == LBN_DBLCLK )
 598     {
 599         evtType = wxEVT_COMMAND_LISTBOX_DOUBLECLICKED;
 600     }
 601     else
 602     {
 603         // some event we're not interested in
 604         return false;
 605     }
 606
 607     // Find the item position if it was a mouse-generated selection event or a
 608     // double click event (which is always generated using the mouse)
 609     if ( n == wxNOT_FOUND )
 610     {
 611         const DWORD pos = ::GetMessagePos();
 612         const wxPoint pt(GET_X_LPARAM(pos), GET_Y_LPARAM(pos));
 613         n = HitTest(ScreenToClient(wxPoint(pt)));
 614     }
 615
 616     // We get events even when mouse is clicked outside of any valid item from
 617     // Windows, just ignore them.
 618     if ( n == wxNOT_FOUND )
 619        return false;
 620
 621     if ( param == LBN_SELCHANGE )
 622     {
 623         if ( !DoChangeSingleSelection(n) )
 624             return false;
 625     }
 626
 627     // Do generate an event otherwise.
 628     return SendEvent(evtType, n, true /* selection */);
 629 }
 630
 631 WXLRESULT
 632 wxListBox::MSWWindowProc(WXUINT nMsg, WXWPARAM wParam, WXLPARAM lParam)
 633 {
 634     // Remember whether there was a keyboard or mouse event before
 635     // LBN_SELCHANGE: this allows us to correctly determine the item affected
 636     // by it in MSWCommand() above in any case.
 637     if ( WM_KEYFIRST <= nMsg && nMsg <= WM_KEYLAST )
 638         m_selectedByKeyboard = true;
 639     else if ( WM_MOUSEFIRST <= nMsg && nMsg <= WM_MOUSELAST )
 640         m_selectedByKeyboard = false;
 641
 642     return wxListBoxBase::MSWWindowProc(nMsg, wParam, lParam);
 643 }
 644
 645 // ----------------------------------------------------------------------------
 646 // owner-drawn list boxes support
 647 // ----------------------------------------------------------------------------
 648
 649 #if wxUSE_OWNER_DRAWN
 650
 651 // misc overloaded methods
 652 // -----------------------
 653
 654 bool wxListBox::SetFont(const wxFont &font)
 655 {
 656     if ( HasFlag(wxLB_OWNERDRAW) )
 657     {
 658         const unsigned count = m_aItems.GetCount();
 659         for ( unsigned i = 0; i < count; i++ )
 660             m_aItems[i]->SetFont(font);
 661     }
 662
 663     wxListBoxBase::SetFont(font);
 664
 665     return true;
 666 }
 667
 668 bool wxListBox::GetItemRect(size_t n, wxRect& rect) const
 669 {
 670     wxCHECK_MSG( IsValid(n), false,
 671                  wxT("invalid index in wxListBox::GetItemRect") );
 672
 673     RECT rc;
 674
 675     if ( ListBox_GetItemRect(GetHwnd(), n, &rc) != LB_ERR )
 676     {
 677         rect = wxRectFromRECT(rc);
 678         return true;
 679     }
 680     else
 681     {
 682         // couldn't retrieve rect: for example, item isn't visible
 683         return false;
 684     }
 685 }
 686
 687 bool wxListBox::RefreshItem(size_t n)
 688 {
 689     wxRect rect;
 690     if ( !GetItemRect(n, rect) )
 691         return false;
 692
 693     RECT rc;
 694     wxCopyRectToRECT(rect, rc);
 695
 696     return ::InvalidateRect((HWND)GetHWND(), &rc, FALSE) == TRUE;
 697 }
 698
 699
 700 // drawing
 701 // -------
 702
 703 namespace
 704 {
 705     // space beneath/above each row in pixels
 706     static const int LISTBOX_EXTRA_SPACE = 1;
 707
 708 } // anonymous namespace
 709
 710 // the height is the same for all items
 711 // TODO should be changed for LBS_OWNERDRAWVARIABLE style listboxes
 712
 713 // NB: can't forward this to wxListBoxItem because LB_SETITEMDATA
 714 //     message is not yet sent when we get here!
 715 bool wxListBox::MSWOnMeasure(WXMEASUREITEMSTRUCT *item)
 716 {
 717     // only owner-drawn control should receive this message
 718     wxCHECK( HasFlag(wxLB_OWNERDRAW), false );
 719
 720     MEASUREITEMSTRUCT *pStruct = (MEASUREITEMSTRUCT *)item;
 721
 722 #ifdef __WXWINCE__
 723     HDC hdc = GetDC(NULL);
 724 #else
 725     HDC hdc = CreateIC(wxT("DISPLAY"), NULL, NULL, 0);
 726 #endif
 727
 728     {
 729         wxDCTemp dc((WXHDC)hdc);
 730         dc.SetFont(GetFont());
 731
 732         pStruct->itemHeight = dc.GetCharHeight() + 2 * LISTBOX_EXTRA_SPACE;
 733         pStruct->itemWidth  = dc.GetCharWidth();
 734     }
 735
 736 #ifdef __WXWINCE__
 737     ReleaseDC(NULL, hdc);
 738 #else
 739     DeleteDC(hdc);
 740 #endif
 741
 742     return true;
 743 }
 744
 745 // forward the message to the appropriate item
 746 bool wxListBox::MSWOnDraw(WXDRAWITEMSTRUCT *item)
 747 {
 748     // only owner-drawn control should receive this message
 749     wxCHECK( HasFlag(wxLB_OWNERDRAW), false );
 750
 751     DRAWITEMSTRUCT *pStruct = (DRAWITEMSTRUCT *)item;
 752
 753     // the item may be -1 for an empty listbox
 754     if ( pStruct->itemID == (UINT)-1 )
 755         return false;
 756
 757     wxListBoxItem *pItem = (wxListBoxItem *)m_aItems[pStruct->itemID];
 758
 759     wxDCTemp dc((WXHDC)pStruct->hDC);
 760
 761     return pItem->OnDrawItem(dc, wxRectFromRECT(pStruct->rcItem),
 762                              (wxOwnerDrawn::wxODAction)pStruct->itemAction,
 763                              (wxOwnerDrawn::wxODStatus)(pStruct->itemState | wxOwnerDrawn::wxODHidePrefix));
 764 }
 765
 766 #endif // wxUSE_OWNER_DRAWN
 767
 768 #endif // wxUSE_LISTBOX