src/msw/combobox.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/combobox.cpp
   3 // Purpose:     wxComboBox class
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 #if wxUSE_COMBOBOX
  28
  29 #include "wx/combobox.h"
  30
  31 #ifndef WX_PRECOMP
  32     #include "wx/settings.h"
  33     #include "wx/log.h"
  34     // for wxEVT_COMMAND_TEXT_ENTER
  35     #include "wx/textctrl.h"
  36     #include "wx/app.h"
  37     #include "wx/brush.h"
  38 #endif
  39
  40 #include "wx/clipbrd.h"
  41 #include "wx/msw/private.h"
  42
  43 // include <commctrl.h> "properly"
  44 #include "wx/msw/wrapcctl.h"
  45
  46 #if wxUSE_TOOLTIPS
  47     #include "wx/tooltip.h"
  48 #endif // wxUSE_TOOLTIPS
  49
  50 // ----------------------------------------------------------------------------
  51 // wxWin macros
  52 // ----------------------------------------------------------------------------
  53
  54 #if wxUSE_EXTENDED_RTTI
  55 WX_DEFINE_FLAGS( wxComboBoxStyle )
  56
  57 wxBEGIN_FLAGS( wxComboBoxStyle )
  58     // new style border flags, we put them first to
  59     // use them for streaming out
  60     wxFLAGS_MEMBER(wxBORDER_SIMPLE)
  61     wxFLAGS_MEMBER(wxBORDER_SUNKEN)
  62     wxFLAGS_MEMBER(wxBORDER_DOUBLE)
  63     wxFLAGS_MEMBER(wxBORDER_RAISED)
  64     wxFLAGS_MEMBER(wxBORDER_STATIC)
  65     wxFLAGS_MEMBER(wxBORDER_NONE)
  66
  67     // old style border flags
  68     wxFLAGS_MEMBER(wxSIMPLE_BORDER)
  69     wxFLAGS_MEMBER(wxSUNKEN_BORDER)
  70     wxFLAGS_MEMBER(wxDOUBLE_BORDER)
  71     wxFLAGS_MEMBER(wxRAISED_BORDER)
  72     wxFLAGS_MEMBER(wxSTATIC_BORDER)
  73     wxFLAGS_MEMBER(wxBORDER)
  74
  75     // standard window styles
  76     wxFLAGS_MEMBER(wxTAB_TRAVERSAL)
  77     wxFLAGS_MEMBER(wxCLIP_CHILDREN)
  78     wxFLAGS_MEMBER(wxTRANSPARENT_WINDOW)
  79     wxFLAGS_MEMBER(wxWANTS_CHARS)
  80     wxFLAGS_MEMBER(wxFULL_REPAINT_ON_RESIZE)
  81     wxFLAGS_MEMBER(wxALWAYS_SHOW_SB )
  82     wxFLAGS_MEMBER(wxVSCROLL)
  83     wxFLAGS_MEMBER(wxHSCROLL)
  84
  85     wxFLAGS_MEMBER(wxCB_SIMPLE)
  86     wxFLAGS_MEMBER(wxCB_SORT)
  87     wxFLAGS_MEMBER(wxCB_READONLY)
  88     wxFLAGS_MEMBER(wxCB_DROPDOWN)
  89
  90 wxEND_FLAGS( wxComboBoxStyle )
  91
  92 IMPLEMENT_DYNAMIC_CLASS_XTI(wxComboBox, wxControl,"wx/combobox.h")
  93
  94 wxBEGIN_PROPERTIES_TABLE(wxComboBox)
  95     wxEVENT_PROPERTY( Select , wxEVT_COMMAND_COMBOBOX_SELECTED , wxCommandEvent )
  96     wxEVENT_PROPERTY( TextEnter , wxEVT_COMMAND_TEXT_ENTER , wxCommandEvent )
  97
  98     // TODO DELEGATES
  99     wxPROPERTY( Font , wxFont , SetFont , GetFont  , EMPTY_MACROVALUE , 0 /*flags*/ , wxT("Helpstring") , wxT("group"))
 100     wxPROPERTY_COLLECTION( Choices , wxArrayString , wxString , AppendString , GetStrings , 0 /*flags*/ , wxT("Helpstring") , wxT("group"))
 101     wxPROPERTY( Value ,wxString, SetValue, GetValue, EMPTY_MACROVALUE , 0 /*flags*/ , wxT("Helpstring") , wxT("group"))
 102     wxPROPERTY( Selection ,int, SetSelection, GetSelection, EMPTY_MACROVALUE , 0 /*flags*/ , wxT("Helpstring") , wxT("group"))
 103     wxPROPERTY_FLAGS( WindowStyle , wxComboBoxStyle , long , SetWindowStyleFlag , GetWindowStyleFlag , EMPTY_MACROVALUE , 0 /*flags*/ , wxT("Helpstring") , wxT("group")) // style
 104 wxEND_PROPERTIES_TABLE()
 105
 106 wxBEGIN_HANDLERS_TABLE(wxComboBox)
 107 wxEND_HANDLERS_TABLE()
 108
 109 wxCONSTRUCTOR_5( wxComboBox , wxWindow* , Parent , wxWindowID , Id , wxString , Value , wxPoint , Position , wxSize , Size )
 110
 111 #else
 112
 113 IMPLEMENT_DYNAMIC_CLASS(wxComboBox, wxControl)
 114
 115 #endif
 116
 117 BEGIN_EVENT_TABLE(wxComboBox, wxControl)
 118     EVT_MENU(wxID_CUT, wxComboBox::OnCut)
 119     EVT_MENU(wxID_COPY, wxComboBox::OnCopy)
 120     EVT_MENU(wxID_PASTE, wxComboBox::OnPaste)
 121     EVT_MENU(wxID_UNDO, wxComboBox::OnUndo)
 122     EVT_MENU(wxID_REDO, wxComboBox::OnRedo)
 123     EVT_MENU(wxID_CLEAR, wxComboBox::OnDelete)
 124     EVT_MENU(wxID_SELECTALL, wxComboBox::OnSelectAll)
 125
 126     EVT_UPDATE_UI(wxID_CUT, wxComboBox::OnUpdateCut)
 127     EVT_UPDATE_UI(wxID_COPY, wxComboBox::OnUpdateCopy)
 128     EVT_UPDATE_UI(wxID_PASTE, wxComboBox::OnUpdatePaste)
 129     EVT_UPDATE_UI(wxID_UNDO, wxComboBox::OnUpdateUndo)
 130     EVT_UPDATE_UI(wxID_REDO, wxComboBox::OnUpdateRedo)
 131     EVT_UPDATE_UI(wxID_CLEAR, wxComboBox::OnUpdateDelete)
 132     EVT_UPDATE_UI(wxID_SELECTALL, wxComboBox::OnUpdateSelectAll)
 133 END_EVENT_TABLE()
 134
 135 // ----------------------------------------------------------------------------
 136 // function prototypes
 137 // ----------------------------------------------------------------------------
 138
 139 LRESULT APIENTRY _EXPORT wxComboEditWndProc(HWND hWnd,
 140                                             UINT message,
 141                                             WPARAM wParam,
 142                                             LPARAM lParam);
 143
 144 // ---------------------------------------------------------------------------
 145 // global vars
 146 // ---------------------------------------------------------------------------
 147
 148 // the pointer to standard radio button wnd proc
 149 static WNDPROC gs_wndprocEdit = (WNDPROC)NULL;
 150
 151 // ============================================================================
 152 // implementation
 153 // ============================================================================
 154
 155 // ----------------------------------------------------------------------------
 156 // wnd proc for subclassed edit control
 157 // ----------------------------------------------------------------------------
 158
 159 LRESULT APIENTRY _EXPORT wxComboEditWndProc(HWND hWnd,
 160                                             UINT message,
 161                                             WPARAM wParam,
 162                                             LPARAM lParam)
 163 {
 164     HWND hwndCombo = ::GetParent(hWnd);
 165     wxWindow *win = wxFindWinFromHandle((WXHWND)hwndCombo);
 166
 167     switch ( message )
 168     {
 169         // forward some messages to the combobox to generate the appropriate
 170         // wxEvents from them
 171         case WM_KEYUP:
 172         case WM_KEYDOWN:
 173         case WM_CHAR:
 174         case WM_SYSCHAR:
 175         case WM_SYSKEYDOWN:
 176         case WM_SYSKEYUP:
 177         case WM_SETFOCUS:
 178         case WM_KILLFOCUS:
 179             {
 180                 wxComboBox *combo = wxDynamicCast(win, wxComboBox);
 181                 if ( !combo )
 182                 {
 183                     // we can get WM_KILLFOCUS while our parent is already half
 184                     // destroyed and hence doesn't look like a combobx any
 185                     // longer, check for it to avoid bogus assert failures
 186                     if ( !win->IsBeingDeleted() )
 187                     {
 188                         wxFAIL_MSG( _T("should have combo as parent") );
 189                     }
 190                 }
 191                 else if ( combo->MSWProcessEditMsg(message, wParam, lParam) )
 192                 {
 193                     // handled by parent
 194                     return 0;
 195                 }
 196             }
 197             break;
 198
 199         case WM_GETDLGCODE:
 200             {
 201                 wxCHECK_MSG( win, 0, _T("should have a parent") );
 202
 203                 if ( win->GetWindowStyle() & wxTE_PROCESS_ENTER )
 204                 {
 205                     // need to return a custom dlg code or we'll never get it
 206                     return DLGC_WANTMESSAGE;
 207                 }
 208             }
 209             break;
 210
 211         case WM_CUT:
 212         case WM_COPY:
 213         case WM_PASTE:
 214             if( win->HandleClipboardEvent( message ) )
 215                 return 0;
 216             break;
 217     }
 218
 219     return ::CallWindowProc(CASTWNDPROC gs_wndprocEdit, hWnd, message, wParam, lParam);
 220 }
 221
 222 // ----------------------------------------------------------------------------
 223 // wxComboBox callbacks
 224 // ----------------------------------------------------------------------------
 225
 226 WXLRESULT wxComboBox::MSWWindowProc(WXUINT nMsg, WXWPARAM wParam, WXLPARAM lParam)
 227 {
 228     // TODO: handle WM_CTLCOLOR messages from our EDIT control to be able to
 229     //       set its colour correctly (to be the same as our own one)
 230
 231     switch ( nMsg )
 232     {
 233         case WM_SIZE:
 234         // wxStaticBox can generate this message, when modifying the control's style.
 235         // This causes the content of the combobox to be selected, for some reason.
 236         case WM_STYLECHANGED:
 237             {
 238                 // combobox selection sometimes spontaneously changes when its
 239                 // size changes, restore it to the old value if necessary
 240                 long fromOld, toOld;
 241                 GetSelection(&fromOld, &toOld);
 242                 WXLRESULT result = wxChoice::MSWWindowProc(nMsg, wParam, lParam);
 243
 244                 long fromNew, toNew;
 245                 GetSelection(&fromNew, &toNew);
 246
 247                 if ( fromOld != fromNew || toOld != toNew )
 248                 {
 249                     SetSelection(fromOld, toOld);
 250                 }
 251
 252                 return result;
 253             }
 254     }
 255
 256     return wxChoice::MSWWindowProc(nMsg, wParam, lParam);
 257 }
 258
 259 bool wxComboBox::MSWProcessEditMsg(WXUINT msg, WXWPARAM wParam, WXLPARAM lParam)
 260 {
 261     switch ( msg )
 262     {
 263         case WM_CHAR:
 264             // for compatibility with wxTextCtrl, generate a special message
 265             // when Enter is pressed
 266             if ( wParam == VK_RETURN )
 267             {
 268                 wxCommandEvent event(wxEVT_COMMAND_TEXT_ENTER, m_windowId);
 269
 270                 const int sel = GetSelection();
 271                 event.SetInt(sel);
 272                 event.SetString(GetValue());
 273                 InitCommandEventWithItems(event, sel);
 274
 275                 if ( ProcessCommand(event) )
 276                 {
 277                     // don't let the event through to the native control
 278                     // because it doesn't need it and may generate an annoying
 279                     // beep if it gets it
 280                     return true;
 281                 }
 282             }
 283             // fall through
 284
 285         case WM_SYSCHAR:
 286             return HandleChar(wParam, lParam, true /* isASCII */);
 287
 288         case WM_SYSKEYDOWN:
 289         case WM_KEYDOWN:
 290             return HandleKeyDown(wParam, lParam);
 291
 292         case WM_SYSKEYUP:
 293         case WM_KEYUP:
 294             return HandleKeyUp(wParam, lParam);
 295
 296         case WM_SETFOCUS:
 297             return HandleSetFocus((WXHWND)wParam);
 298
 299         case WM_KILLFOCUS:
 300             return HandleKillFocus((WXHWND)wParam);
 301     }
 302
 303     return false;
 304 }
 305
 306 bool wxComboBox::MSWCommand(WXUINT param, WXWORD id)
 307 {
 308     int sel = -1;
 309     wxString value;
 310
 311     switch ( param )
 312     {
 313         case CBN_SELENDOK:
 314 #ifndef __SMARTPHONE__
 315             // we need to reset this to prevent the selection from being undone
 316             // by wxChoice, see wxChoice::MSWCommand() and comments there
 317             m_lastAcceptedSelection = wxID_NONE;
 318 #endif
 319
 320             // set these variables so that they could be also fixed in
 321             // CBN_EDITCHANGE below
 322             sel = GetSelection();
 323             value = GetStringSelection();
 324
 325             // this string is going to become the new combobox value soon but
 326             // we need it to be done right now, otherwise the event handler
 327             // could get a wrong value when it calls our GetValue()
 328             ::SetWindowText(GetHwnd(), value);
 329
 330             {
 331                 wxCommandEvent event(wxEVT_COMMAND_COMBOBOX_SELECTED, GetId());
 332                 event.SetInt(sel);
 333                 event.SetString(value);
 334                 InitCommandEventWithItems(event, sel);
 335
 336                 ProcessCommand(event);
 337             }
 338
 339             // fall through: for compability with wxGTK, also send the text
 340             // update event when the selection changes (this also seems more
 341             // logical as the text does change)
 342
 343         case CBN_EDITCHANGE:
 344             {
 345                 wxCommandEvent event(wxEVT_COMMAND_TEXT_UPDATED, GetId());
 346
 347                 // if sel != -1, value was already initialized above
 348                 if ( sel == -1 )
 349                 {
 350                     value = wxGetWindowText(GetHwnd());
 351                 }
 352
 353                 event.SetString(value);
 354                 InitCommandEventWithItems(event, sel);
 355
 356                 ProcessCommand(event);
 357             }
 358             break;
 359
 360         default:
 361             return wxChoice::MSWCommand(param, id);
 362     }
 363
 364     // skip wxChoice version as it would generate its own events for
 365     // CBN_SELENDOK
 366     return wxControl::MSWCommand(param, id);
 367 }
 368
 369 WXHWND wxComboBox::GetEditHWND() const
 370 {
 371     // this function should not be called for wxCB_READONLY controls, it is
 372     // the callers responsability to check this
 373     wxASSERT_MSG( !(GetWindowStyle() & wxCB_READONLY),
 374                   _T("read-only combobox doesn't have any edit control") );
 375
 376     POINT pt;
 377     pt.x = pt.y = 4;
 378     HWND hwndEdit = ::ChildWindowFromPoint(GetHwnd(), pt);
 379     if ( !hwndEdit || hwndEdit == GetHwnd() )
 380     {
 381         wxFAIL_MSG(_T("not read only combobox without edit control?"));
 382     }
 383
 384     return (WXHWND)hwndEdit;
 385 }
 386
 387 // ----------------------------------------------------------------------------
 388 // wxComboBox creation
 389 // ----------------------------------------------------------------------------
 390
 391 bool wxComboBox::Create(wxWindow *parent, wxWindowID id,
 392                         const wxString& value,
 393                         const wxPoint& pos,
 394                         const wxSize& size,
 395                         int n, const wxString choices[],
 396                         long style,
 397                         const wxValidator& validator,
 398                         const wxString& name)
 399 {
 400     // pretend that wxComboBox is hidden while it is positioned and resized and
 401     // show it only right before leaving this method because otherwise there is
 402     // some noticeable flicker while the control rearranges itself
 403     m_isShown = false;
 404
 405     if ( !CreateAndInit(parent, id, pos, size, n, choices, style,
 406                         validator, name) )
 407         return false;
 408
 409     // we shouldn't call SetValue() for an empty string because this would
 410     // (correctly) result in an assert with a read only combobox and is useless
 411     // for the other ones anyhow
 412     if ( !value.empty() )
 413         SetValue(value);
 414
 415     // a (not read only) combobox is, in fact, 2 controls: the combobox itself
 416     // and an edit control inside it and if we want to catch events from this
 417     // edit control, we must subclass it as well
 418     if ( !(style & wxCB_READONLY) )
 419     {
 420         gs_wndprocEdit = wxSetWindowProc((HWND)GetEditHWND(),
 421                                          wxComboEditWndProc);
 422     }
 423
 424     // and finally, show the control
 425     Show(true);
 426
 427     return true;
 428 }
 429
 430 bool wxComboBox::Create(wxWindow *parent, wxWindowID id,
 431                         const wxString& value,
 432                         const wxPoint& pos,
 433                         const wxSize& size,
 434                         const wxArrayString& choices,
 435                         long style,
 436                         const wxValidator& validator,
 437                         const wxString& name)
 438 {
 439     wxCArrayString chs(choices);
 440     return Create(parent, id, value, pos, size, chs.GetCount(),
 441                   chs.GetStrings(), style, validator, name);
 442 }
 443
 444 WXDWORD wxComboBox::MSWGetStyle(long style, WXDWORD *exstyle) const
 445 {
 446     // we never have an external border
 447     WXDWORD msStyle = wxChoice::MSWGetStyle
 448                       (
 449                         (style & ~wxBORDER_MASK) | wxBORDER_NONE, exstyle
 450                       );
 451
 452     // usually WS_TABSTOP is added by wxControl::MSWGetStyle() but as we're
 453     // created hidden (see Create() above), it is not done for us but we still
 454     // want to have this style
 455     msStyle |= WS_TABSTOP;
 456
 457     // remove the style always added by wxChoice
 458     msStyle &= ~CBS_DROPDOWNLIST;
 459
 460     if ( style & wxCB_READONLY )
 461         msStyle |= CBS_DROPDOWNLIST;
 462 #ifndef __WXWINCE__
 463     else if ( style & wxCB_SIMPLE )
 464         msStyle |= CBS_SIMPLE; // A list (shown always) and edit control
 465 #endif
 466     else
 467         msStyle |= CBS_DROPDOWN;
 468
 469     // there is no reason to not always use CBS_AUTOHSCROLL, so do use it
 470     msStyle |= CBS_AUTOHSCROLL;
 471
 472     // NB: we used to also add CBS_NOINTEGRALHEIGHT here but why?
 473
 474     return msStyle;
 475 }
 476
 477 // ----------------------------------------------------------------------------
 478 // wxComboBox text control-like methods
 479 // ----------------------------------------------------------------------------
 480
 481 wxString wxComboBox::GetValue() const
 482 {
 483     return wxGetWindowText(m_hWnd);
 484 }
 485
 486 void wxComboBox::SetValue(const wxString& value)
 487 {
 488     if ( HasFlag(wxCB_READONLY) )
 489         SetStringSelection(value);
 490     else
 491         SetWindowText(GetHwnd(), value.c_str());
 492 }
 493
 494 // Clipboard operations
 495 void wxComboBox::Copy()
 496 {
 497     SendMessage(GetHwnd(), WM_COPY, 0, 0L);
 498 }
 499
 500 void wxComboBox::Cut()
 501 {
 502     SendMessage(GetHwnd(), WM_CUT, 0, 0L);
 503 }
 504
 505 void wxComboBox::Paste()
 506 {
 507     SendMessage(GetHwnd(), WM_PASTE, 0, 0L);
 508 }
 509
 510 void wxComboBox::Undo()
 511 {
 512     if (CanUndo())
 513     {
 514         HWND hEditWnd = (HWND) GetEditHWND();
 515         if ( hEditWnd )
 516             ::SendMessage(hEditWnd, EM_UNDO, 0, 0);
 517     }
 518 }
 519
 520 void wxComboBox::Redo()
 521 {
 522     if (CanUndo())
 523     {
 524         // Same as Undo, since Undo undoes the undo, i.e. a redo.
 525         HWND hEditWnd = (HWND) GetEditHWND();
 526         if ( hEditWnd )
 527             ::SendMessage(hEditWnd, EM_UNDO, 0, 0);
 528     }
 529 }
 530
 531 void wxComboBox::SelectAll()
 532 {
 533     SetSelection(0, GetLastPosition());
 534 }
 535
 536 bool wxComboBox::CanUndo() const
 537 {
 538     if (!IsEditable())
 539         return false;
 540
 541     HWND hEditWnd = (HWND) GetEditHWND();
 542     if ( hEditWnd )
 543         return ::SendMessage(hEditWnd, EM_CANUNDO, 0, 0) != 0;
 544     else
 545         return false;
 546 }
 547
 548 bool wxComboBox::CanRedo() const
 549 {
 550     if (!IsEditable())
 551         return false;
 552
 553     HWND hEditWnd = (HWND) GetEditHWND();
 554     if ( hEditWnd )
 555         return ::SendMessage(hEditWnd, EM_CANUNDO, 0, 0) != 0;
 556     else
 557         return false;
 558 }
 559
 560 bool wxComboBox::HasSelection() const
 561 {
 562     long from, to;
 563     GetSelection(&from, &to);
 564     return from != to;
 565 }
 566
 567 bool wxComboBox::CanCopy() const
 568 {
 569     // Can copy if there's a selection
 570     return HasSelection();
 571 }
 572
 573 bool wxComboBox::CanCut() const
 574 {
 575     return IsEditable() && CanCopy();
 576 }
 577
 578 bool wxComboBox::CanPaste() const
 579 {
 580     if ( !IsEditable() )
 581         return false;
 582
 583     // Standard edit control: check for straight text on clipboard
 584     if ( !::OpenClipboard(GetHwndOf(wxTheApp->GetTopWindow())) )
 585         return false;
 586
 587     bool isTextAvailable = ::IsClipboardFormatAvailable(CF_TEXT) != 0;
 588     ::CloseClipboard();
 589
 590     return isTextAvailable;
 591 }
 592
 593 bool wxComboBox::IsEditable() const
 594 {
 595     return !HasFlag(wxCB_READONLY);
 596 }
 597
 598 void wxComboBox::SetEditable(bool WXUNUSED(editable))
 599 {
 600   // Can't implement in MSW?
 601 //  HWND hWnd = GetHwnd();
 602 //  SendMessage(hWnd, EM_SETREADONLY, (WPARAM)!editable, (LPARAM)0L);
 603 }
 604
 605 void wxComboBox::SetInsertionPoint(long pos)
 606 {
 607     if ( GetWindowStyle() & wxCB_READONLY )
 608         return;
 609
 610 #ifdef __WIN32__
 611     HWND hWnd = GetHwnd();
 612     ::SendMessage(hWnd, CB_SETEDITSEL, 0, MAKELPARAM(pos, pos));
 613     HWND hEditWnd = (HWND) GetEditHWND();
 614     if ( hEditWnd )
 615     {
 616         // Scroll insertion point into view
 617         SendMessage(hEditWnd, EM_SCROLLCARET, (WPARAM)0, (LPARAM)0);
 618         // Why is this necessary? (Copied from wxTextCtrl::SetInsertionPoint)
 619         SendMessage(hEditWnd, EM_REPLACESEL, 0, (LPARAM) wxEmptyString);
 620     }
 621 #endif // __WIN32__
 622 }
 623
 624 void wxComboBox::SetInsertionPointEnd()
 625 {
 626     // setting insertion point doesn't make sense for read only comboboxes
 627     if ( !(GetWindowStyle() & wxCB_READONLY) )
 628     {
 629         wxTextPos pos = GetLastPosition();
 630         SetInsertionPoint(pos);
 631     }
 632 }
 633
 634 long wxComboBox::GetInsertionPoint() const
 635 {
 636     // CB_GETEDITSEL returns the index of the first character of the selection in
 637     // its low-order word
 638     DWORD pos= (DWORD)::SendMessage(GetHwnd(), CB_GETEDITSEL, 0, 0L);
 639     return LOWORD(pos);
 640 }
 641
 642 wxTextPos wxComboBox::GetLastPosition() const
 643 {
 644     HWND hEditWnd = (HWND) GetEditHWND();
 645
 646     // Get number of characters in the last (only) line. We'll add this to the character
 647     // index for the last line, 1st position.
 648     wxTextPos lineLength = (wxTextPos)SendMessage(hEditWnd, EM_LINELENGTH, (WPARAM) 0, (LPARAM)0L);
 649
 650     return lineLength;
 651 }
 652
 653 void wxComboBox::Replace(long from, long to, const wxString& value)
 654 {
 655 #if wxUSE_CLIPBOARD
 656     Remove(from, to);
 657
 658     // Now replace with 'value', by pasting.
 659     wxSetClipboardData(wxDF_TEXT, (wxObject *)(const wxChar *)value, 0, 0);
 660
 661     // Paste into edit control
 662     SendMessage(GetHwnd(), WM_PASTE, (WPARAM)0, (LPARAM)0L);
 663 #else
 664     wxUnusedVar(from);
 665     wxUnusedVar(to);
 666     wxUnusedVar(value);
 667 #endif
 668 }
 669
 670 void wxComboBox::Remove(long from, long to)
 671 {
 672     // Set selection and remove it
 673     SetSelection(from, to);
 674     SendMessage(GetHwnd(), WM_CUT, (WPARAM)0, (LPARAM)0);
 675 }
 676
 677 void wxComboBox::SetSelection(long from, long to)
 678 {
 679     // if from and to are both -1, it means (in wxWidgets) that all text should
 680     // be selected, translate this into Windows convention
 681     if ( (from == -1) && (to == -1) )
 682     {
 683         from = 0;
 684     }
 685
 686     if ( SendMessage(GetHwnd(), CB_SETEDITSEL,
 687                      0, (LPARAM)MAKELONG(from, to)) == CB_ERR )
 688     {
 689         wxLogDebug(_T("CB_SETEDITSEL failed"));
 690     }
 691 }
 692
 693 void wxComboBox::GetSelection(long* from, long* to) const
 694 {
 695     DWORD dwStart, dwEnd;
 696     if ( ::SendMessage(GetHwnd(), CB_GETEDITSEL,
 697                        (WPARAM)&dwStart, (LPARAM)&dwEnd) == CB_ERR )
 698     {
 699         *from =
 700         *to = 0;
 701     }
 702     else
 703     {
 704         *from = dwStart;
 705         *to = dwEnd;
 706     }
 707 }
 708
 709 // ----------------------------------------------------------------------------
 710 // standard event handling
 711 // ----------------------------------------------------------------------------
 712
 713 void wxComboBox::OnCut(wxCommandEvent& WXUNUSED(event))
 714 {
 715     Cut();
 716 }
 717
 718 void wxComboBox::OnCopy(wxCommandEvent& WXUNUSED(event))
 719 {
 720     Copy();
 721 }
 722
 723 void wxComboBox::OnPaste(wxCommandEvent& WXUNUSED(event))
 724 {
 725     Paste();
 726 }
 727
 728 void wxComboBox::OnUndo(wxCommandEvent& WXUNUSED(event))
 729 {
 730     Undo();
 731 }
 732
 733 void wxComboBox::OnRedo(wxCommandEvent& WXUNUSED(event))
 734 {
 735     Redo();
 736 }
 737
 738 void wxComboBox::OnDelete(wxCommandEvent& WXUNUSED(event))
 739 {
 740     long from, to;
 741     GetSelection(& from, & to);
 742     if (from != -1 && to != -1)
 743         Remove(from, to);
 744 }
 745
 746 void wxComboBox::OnSelectAll(wxCommandEvent& WXUNUSED(event))
 747 {
 748     SetSelection(-1, -1);
 749 }
 750
 751 void wxComboBox::OnUpdateCut(wxUpdateUIEvent& event)
 752 {
 753     event.Enable( CanCut() );
 754 }
 755
 756 void wxComboBox::OnUpdateCopy(wxUpdateUIEvent& event)
 757 {
 758     event.Enable( CanCopy() );
 759 }
 760
 761 void wxComboBox::OnUpdatePaste(wxUpdateUIEvent& event)
 762 {
 763     event.Enable( CanPaste() );
 764 }
 765
 766 void wxComboBox::OnUpdateUndo(wxUpdateUIEvent& event)
 767 {
 768     event.Enable( CanUndo() );
 769 }
 770
 771 void wxComboBox::OnUpdateRedo(wxUpdateUIEvent& event)
 772 {
 773     event.Enable( CanRedo() );
 774 }
 775
 776 void wxComboBox::OnUpdateDelete(wxUpdateUIEvent& event)
 777 {
 778     event.Enable(HasSelection() && IsEditable());
 779 }
 780
 781 void wxComboBox::OnUpdateSelectAll(wxUpdateUIEvent& event)
 782 {
 783     event.Enable(GetLastPosition() > 0);
 784 }
 785
 786 #endif // wxUSE_COMBOBOX