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 rectangle occupied by this item in physical coordinates.
 130
 131         If the item is not currently visible, returns an empty rectangle.
 132      */
 133     wxRect GetItemRect(size_t item) const;
 134
 135     /**
 136         Returns the index of the next selected item or @c wxNOT_FOUND if there
 137         are no more.
 138
 139         This method is only valid for multi selection listboxes.
 140
 141         @see GetFirstSelected()
 142     */
 143     int GetNextSelected(unsigned long& cookie) const;
 144
 145     /**
 146         Returns the number of the items currently selected.
 147
 148         It is valid for both single and multi selection controls. In the former
 149         case it may only return 0 or 1 however.
 150
 151         @see IsSelected(), GetFirstSelected(), GetNextSelected()
 152     */
 153     size_t GetSelectedCount() const;
 154
 155     /**
 156         Get the currently selected item or @c wxNOT_FOUND if there is no
 157         selection.
 158     */
 159     int GetSelection() const;
 160
 161     /**
 162         Returns the background colour used for the selected cells. By default
 163         the standard system colour is used.
 164
 165         @see wxSystemSettings::GetColour(), SetSelectionBackground()
 166     */
 167     const wxColour& GetSelectionBackground() const;
 168
 169     /**
 170         Returns @true if the listbox was created with @c wxLB_MULTIPLE style
 171         and so supports multiple selection or @false if it is a single
 172         selection listbox.
 173     */
 174     bool HasMultipleSelection() const;
 175
 176     /**
 177         Returns @true if this item is the current one, @false otherwise.
 178
 179         The current item is always the same as selected one for the single
 180         selection listbox and in this case this method is equivalent to
 181         IsSelected() but they are different for multi selection listboxes where
 182         many items may be selected but only one (at most) is current.
 183     */
 184     bool IsCurrent(size_t item) const;
 185
 186     /**
 187         Returns @true if this item is selected, @false otherwise.
 188     */
 189     bool IsSelected(size_t item) const;
 190
 191     /**
 192         This method is used to draw the items background and, maybe, a border
 193         around it.
 194
 195         The base class version implements a reasonable default behaviour which
 196         consists in drawing the selected item with the standard background
 197         colour and drawing a border around the item if it is either selected or
 198         current.
 199
 200         @todo Change this function signature to non-const.
 201     */
 202     void OnDrawBackground(wxDC& dc, const wxRect& rect, size_t n) const;
 203
 204     /**
 205         The derived class must implement this function to actually draw the
 206         item with the given index on the provided DC.
 207
 208         @param dc
 209             The device context to use for drawing.
 210         @param rect
 211             The bounding rectangle for the item being drawn (DC clipping
 212             region is set to this rectangle before calling this function).
 213         @param n
 214             The index of the item to be drawn.
 215
 216         @todo Change this function signature to non-const.
 217     */
 218     virtual void OnDrawItem(wxDC& dc, const wxRect& rect, size_t n) const;
 219
 220     /**
 221         This method may be used to draw separators between the lines. The
 222         rectangle passed to it may be modified, typically to deflate it a bit
 223         before passing to OnDrawItem().
 224
 225         The base class version of this method doesn't do anything.
 226
 227         @param dc
 228             The device context to use for drawing.
 229         @param rect
 230             The bounding rectangle for the item.
 231         @param n
 232             The index of the item.
 233
 234         @todo Change this function signature to non-const.
 235     */
 236     virtual void OnDrawSeparator(wxDC& dc, wxRect& rect, size_t n) const;
 237
 238     /**
 239         The derived class must implement this method to return the height of
 240         the specified item (in pixels).
 241     */
 242     virtual wxCoord OnMeasureItem(size_t n) const;
 243
 244     /**
 245         Selects or deselects the specified item which must be valid (i.e. not
 246         equal to @c wxNOT_FOUND).
 247
 248         @return @true if the items selection status has changed or @false
 249                  otherwise.
 250
 251         This function is only valid for the multiple selection listboxes, use
 252         SetSelection() for the single selection ones.
 253     */
 254     bool Select(size_t item, bool select = true);
 255
 256     /**
 257         Selects all the items in the listbox.
 258
 259         @return @true if any items were changed, i.e. if there had been any
 260                  unselected items before, or @false if all the items were
 261                  already selected.
 262
 263         This method is only valid for multi selection listboxes.
 264
 265         @see DeselectAll(), Select()
 266     */
 267     bool SelectAll();
 268
 269     /**
 270         Selects all items in the specified range which may be given in any
 271         order.
 272
 273         @return @true if the items selection status has changed or @false
 274                  otherwise.
 275
 276         This method is only valid for multi selection listboxes.
 277
 278         @see SelectAll(), Select()
 279     */
 280     bool SelectRange(size_t from, size_t to);
 281
 282     /**
 283         Set the number of items to be shown in the control.
 284
 285         This is just a synonym for wxVScrolledWindow::SetRowCount().
 286     */
 287     void SetItemCount(size_t count);
 288
 289     //@{
 290     /**
 291         Set the margins: horizontal margin is the distance between the window
 292         border and the item contents while vertical margin is half of the
 293         distance between items.
 294
 295         By default both margins are 0.
 296     */
 297     void SetMargins(const wxPoint& pt);
 298     void SetMargins(wxCoord x, wxCoord y);
 299     //@}
 300
 301     /**
 302         Set the selection to the specified item, if it is -1 the selection is
 303         unset. The selected item will be automatically scrolled into view if it
 304         isn't currently visible.
 305
 306         This method may be used both with single and multiple selection
 307         listboxes.
 308     */
 309     void SetSelection(int selection);
 310
 311     /**
 312         Sets the colour to be used for the selected cells background. The
 313         background of the standard cells may be changed by simply calling
 314         wxWindow::SetBackgroundColour().
 315
 316         @note Using a non-default background colour may result in control
 317               having an appearance different from the similar native controls
 318               and should be avoided in general.
 319
 320         @see GetSelectionBackground()
 321     */
 322     void SetSelectionBackground(const wxColour& col);
 323
 324     /**
 325         Toggles the state of the specified @a item, i.e. selects it if it was
 326         unselected and deselects it if it was selected.
 327
 328         This method is only valid for multi selection listboxes.
 329
 330         @see Select()
 331     */
 332     void Toggle(size_t item);
 333 };
 334