interface/wx/vlbox.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        vlbox.h
   3 // Purpose:     interface of wxVListBox
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxVListBox
  11
  12     wxVListBox is a wxListBox-like control with the following two main
  13     differences from a regular wxListBox: it can have an arbitrarily huge
  14     number of items because it doesn't store them itself but uses the
  15     OnDrawItem() callback to draw them (so it is a virtual listbox) and its
  16     items can have variable height as determined by OnMeasureItem() (so it is
  17     also a listbox with the lines of variable height).
  18
  19     Also, as a consequence of its virtual nature, it doesn't have any methods
  20     to append or insert items in it as it isn't necessary to do it: you just
  21     have to call SetItemCount() to tell the control how many items it should
  22     display. Of course, this also means that you will never use this class
  23     directly because it has pure virtual functions, but will need to derive
  24     your own class from it (for example, wxHtmlListBox).
  25
  26     However it emits the same events as wxListBox and the same event macros may
  27     be used with it. Since wxVListBox does not store its items itself, the
  28     events will only contain the index, not any contents such as the string of
  29     an item.
  30
  31     @library{wxcore}
  32     @category{ctrl}
  33     <!-- @appearance{vlistbox.png} -->
  34
  35     @see wxSimpleHtmlListBox, wxHtmlListBox
  36 */
  37 class wxVListBox : public wxVScrolledWindow
  38 {
  39 public:
  40     /**
  41         Default constructor, you must call Create() later.
  42     */
  43     wxVListBox();
  44     /**
  45         Normal constructor which calls Create() internally.
  46     */
  47     wxVListBox(wxWindow* parent, wxWindowID id = wxID_ANY,
  48                const wxPoint& pos = wxDefaultPosition,
  49                const wxSize& size = wxDefaultSize,
  50                long style = 0, const wxString& name = wxVListBoxNameStr);
  51
  52     /**
  53         Destructor.
  54     */
  55     virtual ~wxVListBox();
  56
  57     /**
  58         Deletes all items from the control.
  59     */
  60     void Clear();
  61
  62     /**
  63         Creates the control. To finish creating it you also should call
  64         SetItemCount() to let it know about the number of items it contains.
  65
  66         The only special style which may be used with wxVListBox is
  67         @c wxLB_MULTIPLE which indicates that the listbox should support
  68         multiple selection.
  69
  70         @return @true on success or @false if the control couldn't be created.
  71     */
  72     bool Create(wxWindow* parent, wxWindowID id = wxID_ANY,
  73                 const wxPoint& pos = wxDefaultPosition,
  74                 const wxSize& size = wxDefaultSize, long style = 0,
  75                 const wxString& name = wxVListBoxNameStr);
  76
  77     /**
  78         Deselects all the items in the listbox. This method is only valid for
  79         multi selection listboxes.
  80
  81         @return @true if any items were changed, i.e. if there had been any
  82                  selected items before, or @false if all the items were already
  83                  deselected.
  84
  85         @see SelectAll(), Select()
  86     */
  87     bool DeselectAll();
  88
  89     /**
  90         Returns the index of the first selected item in the listbox or
  91         @c wxNOT_FOUND if no items are currently selected.
  92
  93         @a cookie is an opaque parameter which should be passed to the
  94         subsequent calls to GetNextSelected(). It is needed in order to allow
  95         parallel iterations over the selected items.
  96
  97         Here is a typical example of using these functions:
  98
  99         @code
 100         unsigned long cookie;
 101         int item = hlbox->GetFirstSelected(cookie);
 102         while ( item != wxNOT_FOUND )
 103         {
 104             // ... process item ...
 105             item = hlbox->GetNextSelected(cookie);
 106         }
 107         @endcode
 108
 109         This method is only valid for multi selection listboxes.
 110     */
 111     int GetFirstSelected(unsigned long& cookie) const;
 112
 113     /**
 114         Get the number of items in the control.
 115
 116         @see SetItemCount()
 117     */
 118     size_t GetItemCount() const;
 119
 120     /**
 121         Returns the margins used by the control. The @c x field of the returned
 122         point is the horizontal margin and the @c y field is the vertical one.
 123
 124         @see SetMargins()
 125     */
 126     wxPoint GetMargins() const;
 127
 128     /**
 129         Returns the index of the next selected item or @c wxNOT_FOUND if there
 130         are no more.
 131
 132         This method is only valid for multi selection listboxes.
 133
 134         @see GetFirstSelected()
 135     */
 136     int GetNextSelected(unsigned long& cookie) const;
 137
 138     /**
 139         Returns the number of the items currently selected.
 140
 141         It is valid for both single and multi selection controls. In the former
 142         case it may only return 0 or 1 however.
 143
 144         @see IsSelected(), GetFirstSelected(), GetNextSelected()
 145     */
 146     size_t GetSelectedCount() const;
 147
 148     /**
 149         Get the currently selected item or @c wxNOT_FOUND if there is no
 150         selection.
 151     */
 152     int GetSelection() const;
 153
 154     /**
 155         Returns the background colour used for the selected cells. By default
 156         the standard system colour is used.
 157
 158         @see wxSystemSettings::GetColour(), SetSelectionBackground()
 159     */
 160     const wxColour& GetSelectionBackground() const;
 161
 162     /**
 163         Returns @true if the listbox was created with @c wxLB_MULTIPLE style
 164         and so supports multiple selection or @false if it is a single
 165         selection listbox.
 166     */
 167     bool HasMultipleSelection() const;
 168
 169     /**
 170         Returns @true if this item is the current one, @false otherwise.
 171
 172         The current item is always the same as selected one for the single
 173         selection listbox and in this case this method is equivalent to
 174         IsSelected() but they are different for multi selection listboxes where
 175         many items may be selected but only one (at most) is current.
 176     */
 177     bool IsCurrent(size_t item) const;
 178
 179     /**
 180         Returns @true if this item is selected, @false otherwise.
 181     */
 182     bool IsSelected(size_t item) const;
 183
 184     /**
 185         This method is used to draw the items background and, maybe, a border
 186         around it.
 187
 188         The base class version implements a reasonable default behaviour which
 189         consists in drawing the selected item with the standard background
 190         colour and drawing a border around the item if it is either selected or
 191         current.
 192
 193         @todo Change this function signature to non-const.
 194     */
 195     void OnDrawBackground(wxDC& dc, const wxRect& rect, size_t n) const;
 196
 197     /**
 198         The derived class must implement this function to actually draw the
 199         item with the given index on the provided DC.
 200
 201         @param dc
 202             The device context to use for drawing.
 203         @param rect
 204             The bounding rectangle for the item being drawn (DC clipping
 205             region is set to this rectangle before calling this function).
 206         @param n
 207             The index of the item to be drawn.
 208
 209         @todo Change this function signature to non-const.
 210     */
 211     virtual void OnDrawItem(wxDC& dc, const wxRect& rect, size_t n) const;
 212
 213     /**
 214         This method may be used to draw separators between the lines. The
 215         rectangle passed to it may be modified, typically to deflate it a bit
 216         before passing to OnDrawItem().
 217
 218         The base class version of this method doesn't do anything.
 219
 220         @param dc
 221             The device context to use for drawing.
 222         @param rect
 223             The bounding rectangle for the item.
 224         @param n
 225             The index of the item.
 226
 227         @todo Change this function signature to non-const.
 228     */
 229     virtual void OnDrawSeparator(wxDC& dc, wxRect& rect, size_t n) const;
 230
 231     /**
 232         The derived class must implement this method to return the height of
 233         the specified item (in pixels).
 234     */
 235     virtual wxCoord OnMeasureItem(size_t n) const;
 236
 237     /**
 238         Selects or deselects the specified item which must be valid (i.e. not
 239         equal to @c wxNOT_FOUND).
 240
 241         @return @true if the items selection status has changed or @false
 242                  otherwise.
 243
 244         This function is only valid for the multiple selection listboxes, use
 245         SetSelection() for the single selection ones.
 246     */
 247     bool Select(size_t item, bool select = true);
 248
 249     /**
 250         Selects all the items in the listbox.
 251
 252         @return @true if any items were changed, i.e. if there had been any
 253                  unselected items before, or @false if all the items were
 254                  already selected.
 255
 256         This method is only valid for multi selection listboxes.
 257
 258         @see DeselectAll(), Select()
 259     */
 260     bool SelectAll();
 261
 262     /**
 263         Selects all items in the specified range which may be given in any
 264         order.
 265
 266         @return @true if the items selection status has changed or @false
 267                  otherwise.
 268
 269         This method is only valid for multi selection listboxes.
 270
 271         @see SelectAll(), Select()
 272     */
 273     bool SelectRange(size_t from, size_t to);
 274
 275     /**
 276         Set the number of items to be shown in the control.
 277
 278         This is just a synonym for wxVScrolledWindow::SetRowCount().
 279     */
 280     void SetItemCount(size_t count);
 281
 282     //@{
 283     /**
 284         Set the margins: horizontal margin is the distance between the window
 285         border and the item contents while vertical margin is half of the
 286         distance between items.
 287
 288         By default both margins are 0.
 289     */
 290     void SetMargins(const wxPoint& pt);
 291     void SetMargins(wxCoord x, wxCoord y);
 292     //@}
 293
 294     /**
 295         Set the selection to the specified item, if it is -1 the selection is
 296         unset. The selected item will be automatically scrolled into view if it
 297         isn't currently visible.
 298
 299         This method may be used both with single and multiple selection
 300         listboxes.
 301     */
 302     void SetSelection(int selection);
 303
 304     /**
 305         Sets the colour to be used for the selected cells background. The
 306         background of the standard cells may be changed by simply calling
 307         wxWindow::SetBackgroundColour().
 308
 309         @note Using a non-default background colour may result in control
 310               having an appearance different from the similar native controls
 311               and should be avoided in general.
 312
 313         @see GetSelectionBackground()
 314     */
 315     void SetSelectionBackground(const wxColour& col);
 316
 317     /**
 318         Toggles the state of the specified @a item, i.e. selects it if it was
 319         unselected and deselects it if it was selected.
 320
 321         This method is only valid for multi selection listboxes.
 322
 323         @see Select()
 324     */
 325     void Toggle(size_t item);
 326 };
 327