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         @since 2.9.0
 134      */
 135     wxRect GetItemRect(size_t item) const;
 136
 137     /**
 138         Returns the index of the next selected item or @c wxNOT_FOUND if there
 139         are no more.
 140
 141         This method is only valid for multi selection listboxes.
 142
 143         @see GetFirstSelected()
 144     */
 145     int GetNextSelected(unsigned long& cookie) const;
 146
 147     /**
 148         Returns the number of the items currently selected.
 149
 150         It is valid for both single and multi selection controls. In the former
 151         case it may only return 0 or 1 however.
 152
 153         @see IsSelected(), GetFirstSelected(), GetNextSelected()
 154     */
 155     size_t GetSelectedCount() const;
 156
 157     /**
 158         Get the currently selected item or @c wxNOT_FOUND if there is no
 159         selection.
 160     */
 161     int GetSelection() const;
 162
 163     /**
 164         Returns the background colour used for the selected cells. By default
 165         the standard system colour is used.
 166
 167         @see wxSystemSettings::GetColour(), SetSelectionBackground()
 168     */
 169     const wxColour& GetSelectionBackground() const;
 170
 171     /**
 172         Returns @true if the listbox was created with @c wxLB_MULTIPLE style
 173         and so supports multiple selection or @false if it is a single
 174         selection listbox.
 175     */
 176     bool HasMultipleSelection() const;
 177
 178     /**
 179         Returns @true if this item is the current one, @false otherwise.
 180
 181         The current item is always the same as selected one for the single
 182         selection listbox and in this case this method is equivalent to
 183         IsSelected() but they are different for multi selection listboxes where
 184         many items may be selected but only one (at most) is current.
 185     */
 186     bool IsCurrent(size_t item) const;
 187
 188     /**
 189         Returns @true if this item is selected, @false otherwise.
 190     */
 191     bool IsSelected(size_t item) const;
 192
 193     /**
 194         This method is used to draw the items background and, maybe, a border
 195         around it.
 196
 197         The base class version implements a reasonable default behaviour which
 198         consists in drawing the selected item with the standard background
 199         colour and drawing a border around the item if it is either selected or
 200         current.
 201
 202         @todo Change this function signature to non-const.
 203     */
 204     virtual void OnDrawBackground(wxDC& dc, const wxRect& rect, size_t n) const;
 205
 206     /**
 207         This method may be used to draw separators between the lines. The
 208         rectangle passed to it may be modified, typically to deflate it a bit
 209         before passing to OnDrawItem().
 210
 211         The base class version of this method doesn't do anything.
 212
 213         @param dc
 214             The device context to use for drawing.
 215         @param rect
 216             The bounding rectangle for the item.
 217         @param n
 218             The index of the item.
 219
 220         @todo Change this function signature to non-const.
 221     */
 222     virtual void OnDrawSeparator(wxDC& dc, wxRect& rect, size_t n) const;
 223
 224     /**
 225         Selects or deselects the specified item which must be valid (i.e. not
 226         equal to @c wxNOT_FOUND).
 227
 228         @return @true if the items selection status has changed or @false
 229                  otherwise.
 230
 231         This function is only valid for the multiple selection listboxes, use
 232         SetSelection() for the single selection ones.
 233     */
 234     bool Select(size_t item, bool select = true);
 235
 236     /**
 237         Selects all the items in the listbox.
 238
 239         @return @true if any items were changed, i.e. if there had been any
 240                  unselected items before, or @false if all the items were
 241                  already selected.
 242
 243         This method is only valid for multi selection listboxes.
 244
 245         @see DeselectAll(), Select()
 246     */
 247     bool SelectAll();
 248
 249     /**
 250         Selects all items in the specified range which may be given in any
 251         order.
 252
 253         @return @true if the items selection status has changed or @false
 254                  otherwise.
 255
 256         This method is only valid for multi selection listboxes.
 257
 258         @see SelectAll(), Select()
 259     */
 260     bool SelectRange(size_t from, size_t to);
 261
 262     /**
 263         Set the number of items to be shown in the control.
 264
 265         This is just a synonym for wxVScrolledWindow::SetRowCount().
 266     */
 267     virtual void SetItemCount(size_t count);
 268
 269     //@{
 270     /**
 271         Set the margins: horizontal margin is the distance between the window
 272         border and the item contents while vertical margin is half of the
 273         distance between items.
 274
 275         By default both margins are 0.
 276     */
 277     void SetMargins(const wxPoint& pt);
 278     void SetMargins(wxCoord x, wxCoord y);
 279     //@}
 280
 281     /**
 282         Set the selection to the specified item, if it is -1 the selection is
 283         unset. The selected item will be automatically scrolled into view if it
 284         isn't currently visible.
 285
 286         This method may be used both with single and multiple selection
 287         listboxes.
 288     */
 289     void SetSelection(int selection);
 290
 291     /**
 292         Sets the colour to be used for the selected cells background. The
 293         background of the standard cells may be changed by simply calling
 294         wxWindow::SetBackgroundColour().
 295
 296         @note Using a non-default background colour may result in control
 297               having an appearance different from the similar native controls
 298               and should be avoided in general.
 299
 300         @see GetSelectionBackground()
 301     */
 302     void SetSelectionBackground(const wxColour& col);
 303
 304     /**
 305         Toggles the state of the specified @a item, i.e. selects it if it was
 306         unselected and deselects it if it was selected.
 307
 308         This method is only valid for multi selection listboxes.
 309
 310         @see Select()
 311     */
 312     void Toggle(size_t item);
 313
 314 protected:
 315
 316     /**
 317         The derived class must implement this function to actually draw the
 318         item with the given index on the provided DC.
 319
 320         @param dc
 321             The device context to use for drawing.
 322         @param rect
 323             The bounding rectangle for the item being drawn (DC clipping
 324             region is set to this rectangle before calling this function).
 325         @param n
 326             The index of the item to be drawn.
 327
 328         @todo Change this function signature to non-const.
 329     */
 330     virtual void OnDrawItem(wxDC& dc, const wxRect& rect, size_t n) const = 0;
 331
 332     /**
 333         The derived class must implement this method to return the height of
 334         the specified item (in pixels).
 335     */
 336     virtual wxCoord OnMeasureItem(size_t n) const = 0;
 337 };
 338