interface/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     @wxheader{vlbox.h}
  12
  13     wxVListBox is a wxListBox-like control with the following two main
  14     differences from a regular wxListBox: it can have an arbitrarily huge
  15     number of items because it doesn't store them itself but uses the
  16     OnDrawItem() callback to draw them (so it is a virtual listbox) and its
  17     items can have variable height as determined by OnMeasureItem() (so it is
  18     also a listbox with the lines of variable height).
  19
  20     Also, as a consequence of its virtual nature, it doesn't have any methods
  21     to append or insert items in it as it isn't necessary to do it: you just
  22     have to call SetItemCount() to tell the control how many items it should
  23     display. Of course, this also means that you will never use this class
  24     directly because it has pure virtual functions, but will need to derive
  25     your own class from it (for example, wxHtmlListBox).
  26
  27     However it emits the same events as wxListBox and the same event macros may
  28     be used with it. Since wxVListBox does not store its items itself, the
  29     events will only contain the index, not any contents such as the string of
  30     an item.
  31
  32     @library{wxcore}
  33     @category{ctrl}
  34     <!-- @appearance{vlistbox.png} -->
  35
  36     @see wxSimpleHtmlListBox, wxHtmlListBox
  37 */
  38 class wxVListBox : public wxVScrolledWindow
  39 {
  40 public:
  41     /**
  42         Default constructor, you must call Create() later.
  43     */
  44     wxVListBox();
  45     /**
  46         Normal constructor which calls Create() internally.
  47     */
  48     wxVListBox(wxWindow* parent, wxWindowID id = wxID_ANY,
  49                const wxPoint& pos = wxDefaultPosition,
  50                const wxSize& size = wxDefaultSize,
  51                long style = 0, const wxString& name = wxVListBoxNameStr);
  52
  53     /**
  54         Destructor.
  55     */
  56     virtual ~wxVListBox();
  57
  58     /**
  59         Deletes all items from the control.
  60     */
  61     void Clear();
  62
  63     /**
  64         Creates the control. To finish creating it you also should call
  65         SetItemCount() to let it know about the number of items it contains.
  66
  67         The only special style which may be used with wxVListBox is
  68         @c wxLB_MULTIPLE which indicates that the listbox should support
  69         multiple selection.
  70
  71         @return @true on success or @false if the control couldn't be created.
  72     */
  73     bool Create(wxWindow* parent, wxWindowID id = wxID_ANY,
  74                 const wxPoint& pos = wxDefaultPosition,
  75                 const wxSize& size = wxDefaultSize, long style = 0,
  76                 const wxString& name = wxVListBoxNameStr);
  77
  78     /**
  79         Deselects all the items in the listbox. This method is only valid for
  80         multi selection listboxes.
  81
  82         @return @true if any items were changed, i.e. if there had been any
  83                  selected items before, or @false if all the items were already
  84                  deselected.
  85
  86         @see SelectAll(), Select()
  87     */
  88     bool DeselectAll();
  89
  90     /**
  91         Returns the index of the first selected item in the listbox or
  92         @c wxNOT_FOUND if no items are currently selected.
  93
  94         @a cookie is an opaque parameter which should be passed to the
  95         subsequent calls to GetNextSelected(). It is needed in order to allow
  96         parallel iterations over the selected items.
  97
  98         Here is a typical example of using these functions:
  99
 100         @code
 101         unsigned long cookie;
 102         int item = hlbox->GetFirstSelected(cookie);
 103         while ( item != wxNOT_FOUND )
 104         {
 105             // ... process item ...
 106             item = hlbox->GetNextSelected(cookie);
 107         }
 108         @endcode
 109
 110         This method is only valid for multi selection listboxes.
 111     */
 112     int GetFirstSelected(unsigned long& cookie) const;
 113
 114     /**
 115         Get the number of items in the control.
 116
 117         @see SetItemCount()
 118     */
 119     size_t GetItemCount() const;
 120
 121     /**
 122         Returns the margins used by the control. The @c x field of the returned
 123         point is the horizontal margin and the @c y field is the vertical one.
 124
 125         @see SetMargins()
 126     */
 127     wxPoint GetMargins() const;
 128
 129     /**
 130         Returns the index of the next selected item or @c wxNOT_FOUND if there
 131         are no more.
 132
 133         This method is only valid for multi selection listboxes.
 134
 135         @see GetFirstSelected()
 136     */
 137     int GetNextSelected(unsigned long& cookie) const;
 138
 139     /**
 140         Returns the number of the items currently selected.
 141
 142         It is valid for both single and multi selection controls. In the former
 143         case it may only return 0 or 1 however.
 144
 145         @see IsSelected(), GetFirstSelected(), GetNextSelected()
 146     */
 147     size_t GetSelectedCount() const;
 148
 149     /**
 150         Get the currently selected item or @c wxNOT_FOUND if there is no
 151         selection.
 152     */
 153     int GetSelection() const;
 154
 155     /**
 156         Returns the background colour used for the selected cells. By default
 157         the standard system colour is used.
 158
 159         @see wxSystemSettings::GetColour(), SetSelectionBackground()
 160     */
 161     const wxColour& GetSelectionBackground() const;
 162
 163     /**
 164         Returns @true if the listbox was created with @c wxLB_MULTIPLE style
 165         and so supports multiple selection or @false if it is a single
 166         selection listbox.
 167     */
 168     bool HasMultipleSelection() const;
 169
 170     /**
 171         Returns @true if this item is the current one, @false otherwise.
 172
 173         The current item is always the same as selected one for the single
 174         selection listbox and in this case this method is equivalent to
 175         IsSelected() but they are different for multi selection listboxes where
 176         many items may be selected but only one (at most) is current.
 177     */
 178     bool IsCurrent(size_t item) const;
 179
 180     /**
 181         Returns @true if this item is selected, @false otherwise.
 182     */
 183     bool IsSelected(size_t item) const;
 184
 185     /**
 186         This method is used to draw the items background and, maybe, a border
 187         around it.
 188
 189         The base class version implements a reasonable default behaviour which
 190         consists in drawing the selected item with the standard background
 191         colour and drawing a border around the item if it is either selected or
 192         current.
 193
 194         @todo Change this function signature to non-const.
 195     */
 196     void OnDrawBackground(wxDC& dc, const wxRect& rect, size_t n) const;
 197
 198     /**
 199         The derived class must implement this function to actually draw the
 200         item with the given index on the provided DC.
 201
 202         @param dc
 203             The device context to use for drawing.
 204         @param rect
 205             The bounding rectangle for the item being drawn (DC clipping
 206             region is set to this rectangle before calling this function).
 207         @param n
 208             The index of the item to be drawn.
 209
 210         @todo Change this function signature to non-const.
 211     */
 212     virtual void OnDrawItem(wxDC& dc, const wxRect& rect, size_t n) const;
 213
 214     /**
 215         This method may be used to draw separators between the lines. The
 216         rectangle passed to it may be modified, typically to deflate it a bit
 217         before passing to OnDrawItem().
 218
 219         The base class version of this method doesn't do anything.
 220
 221         @param dc
 222             The device context to use for drawing.
 223         @param rect
 224             The bounding rectangle for the item.
 225         @param n
 226             The index of the item.
 227
 228         @todo Change this function signature to non-const.
 229     */
 230     virtual void OnDrawSeparator(wxDC& dc, wxRect& rect, size_t n) const;
 231
 232     /**
 233         The derived class must implement this method to return the height of
 234         the specified item (in pixels).
 235     */
 236     virtual wxCoord OnMeasureItem(size_t n) const;
 237
 238     /**
 239         Selects or deselects the specified item which must be valid (i.e. not
 240         equal to @c wxNOT_FOUND).
 241
 242         @return @true if the items selection status has changed or @false
 243                  otherwise.
 244
 245         This function is only valid for the multiple selection listboxes, use
 246         SetSelection() for the single selection ones.
 247     */
 248     bool Select(size_t item, bool select = true);
 249
 250     /**
 251         Selects all the items in the listbox.
 252
 253         @return @true if any items were changed, i.e. if there had been any
 254                  unselected items before, or @false if all the items were
 255                  already selected.
 256
 257         This method is only valid for multi selection listboxes.
 258
 259         @see DeselectAll(), Select()
 260     */
 261     bool SelectAll();
 262
 263     /**
 264         Selects all items in the specified range which may be given in any
 265         order.
 266
 267         @return @true if the items selection status has changed or @false
 268                  otherwise.
 269
 270         This method is only valid for multi selection listboxes.
 271
 272         @see SelectAll(), Select()
 273     */
 274     bool SelectRange(size_t from, size_t to);
 275
 276     /**
 277         Set the number of items to be shown in the control.
 278
 279         This is just a synonym for wxVScrolledWindow::SetRowCount().
 280     */
 281     void SetItemCount(size_t count);
 282
 283     //@{
 284     /**
 285         Set the margins: horizontal margin is the distance between the window
 286         border and the item contents while vertical margin is half of the
 287         distance between items.
 288
 289         By default both margins are 0.
 290     */
 291     void SetMargins(const wxPoint& pt);
 292     void SetMargins(wxCoord x, wxCoord y);
 293     //@}
 294
 295     /**
 296         Set the selection to the specified item, if it is -1 the selection is
 297         unset. The selected item will be automatically scrolled into view if it
 298         isn't currently visible.
 299
 300         This method may be used both with single and multiple selection
 301         listboxes.
 302     */
 303     void SetSelection(int selection);
 304
 305     /**
 306         Sets the colour to be used for the selected cells background. The
 307         background of the standard cells may be changed by simply calling
 308         wxWindow::SetBackgroundColour().
 309
 310         @note Using a non-default background colour may result in control
 311               having an appearance different from the similar native controls
 312               and should be avoided in general.
 313
 314         @see GetSelectionBackground()
 315     */
 316     void SetSelectionBackground(const wxColour& col);
 317
 318     /**
 319         Toggles the state of the specified @a item, i.e. selects it if it was
 320         unselected and deselects it if it was selected.
 321
 322         This method is only valid for multi selection listboxes.
 323
 324         @see Select()
 325     */
 326     void Toggle(size_t item);
 327 };
 328