interface/wx/vlbox.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        vlbox.h
   3 // Purpose:     interface of wxVListBox
   4 // Author:      wxWidgets team
   5 // Licence:     wxWindows licence
   6 /////////////////////////////////////////////////////////////////////////////
   7
   8 /**
   9     @class wxVListBox
  10
  11     wxVListBox is a wxListBox-like control with the following two main
  12     differences from a regular wxListBox: it can have an arbitrarily huge
  13     number of items because it doesn't store them itself but uses the
  14     OnDrawItem() callback to draw them (so it is a virtual listbox) and its
  15     items can have variable height as determined by OnMeasureItem() (so it is
  16     also a listbox with the lines of variable height).
  17
  18     Also, as a consequence of its virtual nature, it doesn't have any methods
  19     to append or insert items in it as it isn't necessary to do it: you just
  20     have to call SetItemCount() to tell the control how many items it should
  21     display. Of course, this also means that you will never use this class
  22     directly because it has pure virtual functions, but will need to derive
  23     your own class from it (for example, wxHtmlListBox).
  24
  25     However it emits the same events as wxListBox and the same event macros may
  26     be used with it. Since wxVListBox does not store its items itself, the
  27     events will only contain the index, not any contents such as the string of
  28     an item.
  29
  30     @library{wxcore}
  31     @category{ctrl}
  32
  33     @see wxSimpleHtmlListBox, wxHtmlListBox
  34 */
  35 class wxVListBox : public wxVScrolledWindow
  36 {
  37 public:
  38     /**
  39         Default constructor, you must call Create() later.
  40     */
  41     wxVListBox();
  42     /**
  43         Normal constructor which calls Create() internally.
  44     */
  45     wxVListBox(wxWindow* parent, wxWindowID id = wxID_ANY,
  46                const wxPoint& pos = wxDefaultPosition,
  47                const wxSize& size = wxDefaultSize,
  48                long style = 0, const wxString& name = wxVListBoxNameStr);
  49
  50     /**
  51         Destructor.
  52     */
  53     virtual ~wxVListBox();
  54
  55     /**
  56         Deletes all items from the control.
  57     */
  58     void Clear();
  59
  60     /**
  61         Creates the control. To finish creating it you also should call
  62         SetItemCount() to let it know about the number of items it contains.
  63
  64         The only special style which may be used with wxVListBox is
  65         @c wxLB_MULTIPLE which indicates that the listbox should support
  66         multiple selection.
  67
  68         @return @true on success or @false if the control couldn't be created.
  69     */
  70     bool Create(wxWindow* parent, wxWindowID id = wxID_ANY,
  71                 const wxPoint& pos = wxDefaultPosition,
  72                 const wxSize& size = wxDefaultSize, long style = 0,
  73                 const wxString& name = wxVListBoxNameStr);
  74
  75     /**
  76         Deselects all the items in the listbox. This method is only valid for
  77         multi selection listboxes.
  78
  79         @return @true if any items were changed, i.e. if there had been any
  80                  selected items before, or @false if all the items were already
  81                  deselected.
  82
  83         @see SelectAll(), Select()
  84     */
  85     bool DeselectAll();
  86
  87     /**
  88         Returns the index of the first selected item in the listbox or
  89         @c wxNOT_FOUND if no items are currently selected.
  90
  91         @a cookie is an opaque parameter which should be passed to the
  92         subsequent calls to GetNextSelected(). It is needed in order to allow
  93         parallel iterations over the selected items.
  94
  95         Here is a typical example of using these functions:
  96
  97         @code
  98         unsigned long cookie;
  99         int item = hlbox->GetFirstSelected(cookie);
 100         while ( item != wxNOT_FOUND )
 101         {
 102             // ... process item ...
 103             item = hlbox->GetNextSelected(cookie);
 104         }
 105         @endcode
 106
 107         This method is only valid for multi selection listboxes.
 108     */
 109     int GetFirstSelected(unsigned long& cookie) const;
 110
 111     /**
 112         Get the number of items in the control.
 113
 114         @see SetItemCount()
 115     */
 116     size_t GetItemCount() const;
 117
 118     /**
 119         Returns the margins used by the control. The @c x field of the returned
 120         point is the horizontal margin and the @c y field is the vertical one.
 121
 122         @see SetMargins()
 123     */
 124     wxPoint GetMargins() const;
 125
 126     /**
 127         Returns the rectangle occupied by this item in physical coordinates.
 128
 129         If the item is not currently visible, returns an empty rectangle.
 130
 131         @since 2.9.0
 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         Selects or deselects the specified item which must be valid (i.e.\ not
 193         equal to @c wxNOT_FOUND).
 194
 195         @return @true if the items selection status has changed or @false
 196                  otherwise.
 197
 198         This function is only valid for the multiple selection listboxes, use
 199         SetSelection() for the single selection ones.
 200     */
 201     bool Select(size_t item, bool select = true);
 202
 203     /**
 204         Selects all the items in the listbox.
 205
 206         @return @true if any items were changed, i.e. if there had been any
 207                  unselected items before, or @false if all the items were
 208                  already selected.
 209
 210         This method is only valid for multi selection listboxes.
 211
 212         @see DeselectAll(), Select()
 213     */
 214     bool SelectAll();
 215
 216     /**
 217         Selects all items in the specified range which may be given in any
 218         order.
 219
 220         @return @true if the items selection status has changed or @false
 221                  otherwise.
 222
 223         This method is only valid for multi selection listboxes.
 224
 225         @see SelectAll(), Select()
 226     */
 227     bool SelectRange(size_t from, size_t to);
 228
 229     /**
 230         Set the number of items to be shown in the control.
 231
 232         This is just a synonym for wxVScrolledWindow::SetRowCount().
 233     */
 234     virtual void SetItemCount(size_t count);
 235
 236     //@{
 237     /**
 238         Set the margins: horizontal margin is the distance between the window
 239         border and the item contents while vertical margin is half of the
 240         distance between items.
 241
 242         By default both margins are 0.
 243     */
 244     void SetMargins(const wxPoint& pt);
 245     void SetMargins(wxCoord x, wxCoord y);
 246     //@}
 247
 248     /**
 249         Set the selection to the specified item, if it is -1 the selection is
 250         unset. The selected item will be automatically scrolled into view if it
 251         isn't currently visible.
 252
 253         This method may be used both with single and multiple selection
 254         listboxes.
 255     */
 256     void SetSelection(int selection);
 257
 258     /**
 259         Sets the colour to be used for the selected cells background. The
 260         background of the standard cells may be changed by simply calling
 261         wxWindow::SetBackgroundColour().
 262
 263         @note Using a non-default background colour may result in control
 264               having an appearance different from the similar native controls
 265               and should be avoided in general.
 266
 267         @see GetSelectionBackground()
 268     */
 269     void SetSelectionBackground(const wxColour& col);
 270
 271     /**
 272         Toggles the state of the specified @a item, i.e.\ selects it if it was
 273         unselected and deselects it if it was selected.
 274
 275         This method is only valid for multi selection listboxes.
 276
 277         @see Select()
 278     */
 279     void Toggle(size_t item);
 280
 281 protected:
 282
 283     /**
 284         The derived class must implement this function to actually draw the
 285         item with the given index on the provided DC.
 286
 287         @param dc
 288             The device context to use for drawing.
 289         @param rect
 290             The bounding rectangle for the item being drawn (DC clipping
 291             region is set to this rectangle before calling this function).
 292         @param n
 293             The index of the item to be drawn.
 294
 295         @todo Change this function signature to non-const.
 296     */
 297     virtual void OnDrawItem(wxDC& dc, const wxRect& rect, size_t n) const = 0;
 298
 299     /**
 300         This method is used to draw the item's background and, maybe, a border
 301         around it.
 302
 303         The base class version implements a reasonable default behaviour which
 304         consists in drawing the selected item with the standard background
 305         colour and drawing a border around the item if it is either selected or
 306         current.
 307
 308         @todo Change this function signature to non-const.
 309     */
 310     virtual void OnDrawBackground(wxDC& dc, const wxRect& rect, size_t n) const;
 311
 312     /**
 313         This method may be used to draw separators between the lines. The
 314         rectangle passed to it may be modified, typically to deflate it a bit
 315         before passing to OnDrawItem().
 316
 317         The base class version of this method doesn't do anything.
 318
 319         @param dc
 320             The device context to use for drawing.
 321         @param rect
 322             The bounding rectangle for the item.
 323         @param n
 324             The index of the item.
 325
 326         @todo Change this function signature to non-const.
 327     */
 328     virtual void OnDrawSeparator(wxDC& dc, wxRect& rect, size_t n) const;
 329
 330     /**
 331         The derived class must implement this method to return the height of
 332         the specified item (in pixels).
 333     */
 334     virtual wxCoord OnMeasureItem(size_t n) const = 0;
 335 };
 336