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
  34     @see wxSimpleHtmlListBox, wxHtmlListBox
  35 */
  36 class wxVListBox : public wxVScrolledWindow
  37 {
  38 public:
  39     /**
  40         Default constructor, you must call Create() later.
  41     */
  42     wxVListBox();
  43     /**
  44         Normal constructor which calls Create() internally.
  45     */
  46     wxVListBox(wxWindow* parent, wxWindowID id = wxID_ANY,
  47                const wxPoint& pos = wxDefaultPosition,
  48                const wxSize& size = wxDefaultSize,
  49                long style = 0, const wxString& name = wxVListBoxNameStr);
  50
  51     /**
  52         Destructor.
  53     */
  54     virtual ~wxVListBox();
  55
  56     /**
  57         Deletes all items from the control.
  58     */
  59     void Clear();
  60
  61     /**
  62         Creates the control. To finish creating it you also should call
  63         SetItemCount() to let it know about the number of items it contains.
  64
  65         The only special style which may be used with wxVListBox is
  66         @c wxLB_MULTIPLE which indicates that the listbox should support
  67         multiple selection.
  68
  69         @return @true on success or @false if the control couldn't be created.
  70     */
  71     bool Create(wxWindow* parent, wxWindowID id = wxID_ANY,
  72                 const wxPoint& pos = wxDefaultPosition,
  73                 const wxSize& size = wxDefaultSize, long style = 0,
  74                 const wxString& name = wxVListBoxNameStr);
  75
  76     /**
  77         Deselects all the items in the listbox. This method is only valid for
  78         multi selection listboxes.
  79
  80         @return @true if any items were changed, i.e. if there had been any
  81                  selected items before, or @false if all the items were already
  82                  deselected.
  83
  84         @see SelectAll(), Select()
  85     */
  86     bool DeselectAll();
  87
  88     /**
  89         Returns the index of the first selected item in the listbox or
  90         @c wxNOT_FOUND if no items are currently selected.
  91
  92         @a cookie is an opaque parameter which should be passed to the
  93         subsequent calls to GetNextSelected(). It is needed in order to allow
  94         parallel iterations over the selected items.
  95
  96         Here is a typical example of using these functions:
  97
  98         @code
  99         unsigned long cookie;
 100         int item = hlbox->GetFirstSelected(cookie);
 101         while ( item != wxNOT_FOUND )
 102         {
 103             // ... process item ...
 104             item = hlbox->GetNextSelected(cookie);
 105         }
 106         @endcode
 107
 108         This method is only valid for multi selection listboxes.
 109     */
 110     int GetFirstSelected(unsigned long& cookie) const;
 111
 112     /**
 113         Get the number of items in the control.
 114
 115         @see SetItemCount()
 116     */
 117     size_t GetItemCount() const;
 118
 119     /**
 120         Returns the margins used by the control. The @c x field of the returned
 121         point is the horizontal margin and the @c y field is the vertical one.
 122
 123         @see SetMargins()
 124     */
 125     wxPoint GetMargins() const;
 126
 127     /**
 128         Returns the rectangle occupied by this item in physical coordinates.
 129
 130         If the item is not currently visible, returns an empty rectangle.
 131
 132         @since 2.9.0
 133      */
 134     wxRect GetItemRect(size_t item) const;
 135
 136     /**
 137         Returns the index of the next selected item or @c wxNOT_FOUND if there
 138         are no more.
 139
 140         This method is only valid for multi selection listboxes.
 141
 142         @see GetFirstSelected()
 143     */
 144     int GetNextSelected(unsigned long& cookie) const;
 145
 146     /**
 147         Returns the number of the items currently selected.
 148
 149         It is valid for both single and multi selection controls. In the former
 150         case it may only return 0 or 1 however.
 151
 152         @see IsSelected(), GetFirstSelected(), GetNextSelected()
 153     */
 154     size_t GetSelectedCount() const;
 155
 156     /**
 157         Get the currently selected item or @c wxNOT_FOUND if there is no
 158         selection.
 159     */
 160     int GetSelection() const;
 161
 162     /**
 163         Returns the background colour used for the selected cells. By default
 164         the standard system colour is used.
 165
 166         @see wxSystemSettings::GetColour(), SetSelectionBackground()
 167     */
 168     const wxColour& GetSelectionBackground() const;
 169
 170     /**
 171         Returns @true if the listbox was created with @c wxLB_MULTIPLE style
 172         and so supports multiple selection or @false if it is a single
 173         selection listbox.
 174     */
 175     bool HasMultipleSelection() const;
 176
 177     /**
 178         Returns @true if this item is the current one, @false otherwise.
 179
 180         The current item is always the same as selected one for the single
 181         selection listbox and in this case this method is equivalent to
 182         IsSelected() but they are different for multi selection listboxes where
 183         many items may be selected but only one (at most) is current.
 184     */
 185     bool IsCurrent(size_t item) const;
 186
 187     /**
 188         Returns @true if this item is selected, @false otherwise.
 189     */
 190     bool IsSelected(size_t item) const;
 191
 192     /**
 193         Selects or deselects the specified item which must be valid (i.e. not
 194         equal to @c wxNOT_FOUND).
 195
 196         @return @true if the items selection status has changed or @false
 197                  otherwise.
 198
 199         This function is only valid for the multiple selection listboxes, use
 200         SetSelection() for the single selection ones.
 201     */
 202     bool Select(size_t item, bool select = true);
 203
 204     /**
 205         Selects all the items in the listbox.
 206
 207         @return @true if any items were changed, i.e. if there had been any
 208                  unselected items before, or @false if all the items were
 209                  already selected.
 210
 211         This method is only valid for multi selection listboxes.
 212
 213         @see DeselectAll(), Select()
 214     */
 215     bool SelectAll();
 216
 217     /**
 218         Selects all items in the specified range which may be given in any
 219         order.
 220
 221         @return @true if the items selection status has changed or @false
 222                  otherwise.
 223
 224         This method is only valid for multi selection listboxes.
 225
 226         @see SelectAll(), Select()
 227     */
 228     bool SelectRange(size_t from, size_t to);
 229
 230     /**
 231         Set the number of items to be shown in the control.
 232
 233         This is just a synonym for wxVScrolledWindow::SetRowCount().
 234     */
 235     virtual void SetItemCount(size_t count);
 236
 237     //@{
 238     /**
 239         Set the margins: horizontal margin is the distance between the window
 240         border and the item contents while vertical margin is half of the
 241         distance between items.
 242
 243         By default both margins are 0.
 244     */
 245     void SetMargins(const wxPoint& pt);
 246     void SetMargins(wxCoord x, wxCoord y);
 247     //@}
 248
 249     /**
 250         Set the selection to the specified item, if it is -1 the selection is
 251         unset. The selected item will be automatically scrolled into view if it
 252         isn't currently visible.
 253
 254         This method may be used both with single and multiple selection
 255         listboxes.
 256     */
 257     void SetSelection(int selection);
 258
 259     /**
 260         Sets the colour to be used for the selected cells background. The
 261         background of the standard cells may be changed by simply calling
 262         wxWindow::SetBackgroundColour().
 263
 264         @note Using a non-default background colour may result in control
 265               having an appearance different from the similar native controls
 266               and should be avoided in general.
 267
 268         @see GetSelectionBackground()
 269     */
 270     void SetSelectionBackground(const wxColour& col);
 271
 272     /**
 273         Toggles the state of the specified @a item, i.e. selects it if it was
 274         unselected and deselects it if it was selected.
 275
 276         This method is only valid for multi selection listboxes.
 277
 278         @see Select()
 279     */
 280     void Toggle(size_t item);
 281
 282 protected:
 283
 284     /**
 285         The derived class must implement this function to actually draw the
 286         item with the given index on the provided DC.
 287
 288         @param dc
 289             The device context to use for drawing.
 290         @param rect
 291             The bounding rectangle for the item being drawn (DC clipping
 292             region is set to this rectangle before calling this function).
 293         @param n
 294             The index of the item to be drawn.
 295
 296         @todo Change this function signature to non-const.
 297     */
 298     virtual void OnDrawItem(wxDC& dc, const wxRect& rect, size_t n) const = 0;
 299
 300     /**
 301         This method is used to draw the items background and, maybe, a border
 302         around it.
 303
 304         The base class version implements a reasonable default behaviour which
 305         consists in drawing the selected item with the standard background
 306         colour and drawing a border around the item if it is either selected or
 307         current.
 308
 309         @todo Change this function signature to non-const.
 310     */
 311     virtual void OnDrawBackground(wxDC& dc, const wxRect& rect, size_t n) const;
 312
 313     /**
 314         This method may be used to draw separators between the lines. The
 315         rectangle passed to it may be modified, typically to deflate it a bit
 316         before passing to OnDrawItem().
 317
 318         The base class version of this method doesn't do anything.
 319
 320         @param dc
 321             The device context to use for drawing.
 322         @param rect
 323             The bounding rectangle for the item.
 324         @param n
 325             The index of the item.
 326
 327         @todo Change this function signature to non-const.
 328     */
 329     virtual void OnDrawSeparator(wxDC& dc, wxRect& rect, size_t n) const;
 330
 331     /**
 332         The derived class must implement this method to return the height of
 333         the specified item (in pixels).
 334     */
 335     virtual wxCoord OnMeasureItem(size_t n) const = 0;
 336 };
 337