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         @returns @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         @returns @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     void OnDrawBackground(wxDC& dc, const wxRect& rect, size_t n) const;
 195
 196     /**
 197         The derived class must implement this function to actually draw the
 198         item with the given index on the provided DC.
 199
 200         @param dc
 201             The device context to use for drawing.
 202         @param rect
 203             The bounding rectangle for the item being drawn (DC clipping
 204             region is set to this rectangle before calling this function).
 205         @param n
 206             The index of the item to be drawn.
 207     */
 208     virtual void OnDrawItem(wxDC& dc, const wxRect& rect, size_t n) const;
 209
 210     /**
 211         This method may be used to draw separators between the lines. The
 212         rectangle passed to it may be modified, typically to deflate it a bit
 213         before passing to OnDrawItem().
 214
 215         The base class version of this method doesn't do anything.
 216
 217         @param dc
 218             The device context to use for drawing.
 219         @param rect
 220             The bounding rectangle for the item.
 221         @param n
 222             The index of the item.
 223     */
 224     virtual void OnDrawSeparator(wxDC& dc, wxRect& rect, size_t n) const;
 225
 226     /**
 227         The derived class must implement this method to return the height of
 228         the specified item (in pixels).
 229     */
 230     virtual wxCoord OnMeasureItem(size_t n) const;
 231
 232     /**
 233         Selects or deselects the specified item which must be valid (i.e. not
 234         equal to @c wxNOT_FOUND).
 235
 236         @returns @true if the items selection status has changed or @false
 237                  otherwise.
 238
 239         This function is only valid for the multiple selection listboxes, use
 240         SetSelection() for the single selection ones.
 241     */
 242     bool Select(size_t item, bool select = true);
 243
 244     /**
 245         Selects all the items in the listbox.
 246
 247         @returns @true if any items were changed, i.e. if there had been any
 248                  unselected items before, or @false if all the items were
 249                  already selected.
 250
 251         This method is only valid for multi selection listboxes.
 252
 253         @see DeselectAll(), Select()
 254     */
 255     bool SelectAll();
 256
 257     /**
 258         Selects all items in the specified range which may be given in any
 259         order.
 260
 261         @returns @true if the items selection status has changed or @false
 262                  otherwise.
 263
 264         This method is only valid for multi selection listboxes.
 265
 266         @see SelectAll(), Select()
 267     */
 268     bool SelectRange(size_t from, size_t to);
 269
 270     /**
 271         Set the number of items to be shown in the control.
 272
 273         This is just a synonym for wxVScrolledWindow::SetRowCount().
 274     */
 275     void SetItemCount(size_t count);
 276
 277     //@{
 278     /**
 279         Set the margins: horizontal margin is the distance between the window
 280         border and the item contents while vertical margin is half of the
 281         distance between items.
 282
 283         By default both margins are 0.
 284     */
 285     void SetMargins(const wxPoint& pt);
 286     void SetMargins(wxCoord x, wxCoord y);
 287     //@}
 288
 289     /**
 290         Set the selection to the specified item, if it is -1 the selection is
 291         unset. The selected item will be automatically scrolled into view if it
 292         isn't currently visible.
 293
 294         This method may be used both with single and multiple selection
 295         listboxes.
 296     */
 297     void SetSelection(int selection);
 298
 299     /**
 300         Sets the colour to be used for the selected cells background. The
 301         background of the standard cells may be changed by simply calling
 302         wxWindow::SetBackgroundColour().
 303
 304         @note Using a non-default background colour may result in control
 305               having an appearance different from the similar native controls
 306               and should be avoided in general.
 307
 308         @see GetSelectionBackground()
 309     */
 310     void SetSelectionBackground(const wxColour& col);
 311
 312     /**
 313         Toggles the state of the specified @a item, i.e. selects it if it was
 314         unselected and deselects it if it was selected.
 315
 316         This method is only valid for multi selection listboxes.
 317
 318         @see Select()
 319     */
 320     void Toggle(size_t item);
 321 };
 322