Add wxPropertyGrid screenshots

[wxWidgets.git] / interface / wx / propgrid / propgrid.h

/////////////////////////////////////////////////////////////////////////////
// Name:        propgrid.h
// Purpose:     interface of wxPropertyGrid
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////


/**
    @section propgrid_window_styles wxPropertyGrid Window Styles

    SetWindowStyleFlag method can be used to modify some of these at run-time.
    @{
*/
enum wxPG_WINDOW_STYLES
{

/**
    This will cause Sort() automatically after an item is added.
    When inserting a lot of items in this mode, it may make sense to
    use Freeze() before operations and Thaw() afterwards to increase
    performance.
*/
wxPG_AUTO_SORT                      = 0x00000010,

/**
    Categories are not initially shown (even if added).
    IMPORTANT NOTE: If you do not plan to use categories, then this
    style will waste resources.
    This flag can also be changed using wxPropertyGrid::EnableCategories method.
*/
wxPG_HIDE_CATEGORIES                = 0x00000020,

/*
    This style combines non-categoric mode and automatic sorting.
*/
wxPG_ALPHABETIC_MODE                = (wxPG_HIDE_CATEGORIES|wxPG_AUTO_SORT),

/**
    Modified values are shown in bold font. Changing this requires Refresh()
    to show changes.
*/
wxPG_BOLD_MODIFIED                  = 0x00000040,

/**
    When wxPropertyGrid is resized, splitter moves to the center. This
    behavior stops once the user manually moves the splitter.
*/
wxPG_SPLITTER_AUTO_CENTER           = 0x00000080,

/**
    Display tool tips for cell text that cannot be shown completely. If
    wxUSE_TOOLTIPS is 0, then this doesn't have any effect.
*/
wxPG_TOOLTIPS                       = 0x00000100,

/**
    Disables margin and hides all expand/collapse buttons that would appear
    outside the margin (for sub-properties). Toggling this style automatically
    expands all collapsed items.
*/
wxPG_HIDE_MARGIN                    = 0x00000200,

/**
    This style prevents user from moving the splitter.
*/
wxPG_STATIC_SPLITTER                = 0x00000400,

/**
    Combination of other styles that make it impossible for user to modify
    the layout.
*/
wxPG_STATIC_LAYOUT                  = (wxPG_HIDE_MARGIN|wxPG_STATIC_SPLITTER),

/**
    Disables wxTextCtrl based editors for properties which
    can be edited in another way. Equals calling
    wxPropertyGrid::LimitPropertyEditing() for all added properties.
*/
wxPG_LIMITED_EDITING                = 0x00000800,

/**
    wxPropertyGridManager only: Show tool bar for mode and page selection.
*/
wxPG_TOOLBAR                        = 0x00001000,

/**
    wxPropertyGridManager only: Show adjustable text box showing description
    or help text, if available, for currently selected property.
*/
wxPG_DESCRIPTION                    = 0x00002000

};

enum wxPG_EX_WINDOW_STYLES
{

/**
    NOTE: wxPG_EX_xxx are extra window styles and must be set using SetExtraStyle()
    member function.

    Speeds up switching to wxPG_HIDE_CATEGORIES mode. Initially, if
    wxPG_HIDE_CATEGORIES is not defined, the non-categorized data storage is not
    activated, and switching the mode first time becomes somewhat slower.
    wxPG_EX_INIT_NOCAT activates the non-categorized data storage right away.

    NOTE: If you do plan not switching to non-categoric mode, or if
    you don't plan to use categories at all, then using this style will result
    in waste of resources.
*/
wxPG_EX_INIT_NOCAT                  = 0x00001000,

/**
    Extended window style that sets wxPropertyGridManager tool bar to not
    use flat style.
*/
wxPG_EX_NO_FLAT_TOOLBAR             = 0x00002000,

/**
    Shows alphabetic/categoric mode buttons from tool bar.
*/
wxPG_EX_MODE_BUTTONS                = 0x00008000,

/**
    Show property help strings as tool tips instead as text on the status bar.
    You can set the help strings using SetPropertyHelpString member function.
*/
wxPG_EX_HELP_AS_TOOLTIPS            = 0x00010000,

/**
    Allows relying on native double-buffering.
*/
wxPG_EX_NATIVE_DOUBLE_BUFFERING         = 0x00080000,

/**
    Set this style to let user have ability to set values of properties to
    unspecified state. Same as setting wxPG_PROP_AUTO_UNSPECIFIED for
    all properties.
*/
wxPG_EX_AUTO_UNSPECIFIED_VALUES         = 0x00200000,

/**
    If this style is used, built-in attributes (such as wxPG_FLOAT_PRECISION and
    wxPG_STRING_PASSWORD) are not stored into property's attribute storage (thus
    they are not readable).

    Note that this option is global, and applies to all wxPG property containers.
*/
wxPG_EX_WRITEONLY_BUILTIN_ATTRIBUTES    = 0x00400000,

/**
    Hides page selection buttons from tool bar.
*/
wxPG_EX_HIDE_PAGE_BUTTONS               = 0x01000000

};

/** Combines various styles.
*/
#define wxPG_DEFAULT_STYLE	        (0)

/** Combines various styles.
*/
#define wxPGMAN_DEFAULT_STYLE	    (0)

/** @}
*/

// -----------------------------------------------------------------------

/**
    @section propgrid_vfbflags wxPropertyGrid Validation Failure Behavior Flags
    @{
*/

enum wxPG_VALIDATION_FAILURE_BEHAVIOR_FLAGS
{

/**
    Prevents user from leaving property unless value is valid. If this
    behavior flag is not used, then value change is instead cancelled.
*/
wxPG_VFB_STAY_IN_PROPERTY           = 0x01,

/**
    Calls wxBell() on validation failure.
*/
wxPG_VFB_BEEP                       = 0x02,

/**
    Cell with invalid value will be marked (with red colour).
*/
wxPG_VFB_MARK_CELL                  = 0x04,

/**
    Display customizable text message explaining the situation.
*/
wxPG_VFB_SHOW_MESSAGE               = 0x08,

/**
    Defaults.
*/
wxPG_VFB_DEFAULT                    = wxPG_VFB_STAY_IN_PROPERTY|wxPG_VFB_BEEP,
};

/** @}
*/

typedef wxByte wxPGVFBFlags;

/**
    wxPGValidationInfo

    Used to convey validation information to and from functions that
    actually perform validation. Mostly used in custom property
    classes.
*/
class wxPGValidationInfo
{
public:
    /**
        @return Returns failure behavior which is a combination of
               @ref propgrid_vfbflags.
    */
    wxPGVFBFlags GetFailureBehavior();

    /**
        Returns current failure message.
    */
    const wxString& GetFailureMessage() const;

    /**
        Returns reference to pending value.
    */
    const wxVariant& GetValue() const;

    /** Set validation failure behavior

        @param failureBehavior
            Mixture of @ref propgrid_vfbflags.
    */
    void SetFailureBehavior(wxPGVFBFlags failureBehavior);

    /**
        Set current failure message.
    */
    void SetFailureMessage(const wxString& message);
};

// -----------------------------------------------------------------------

/**
    @section propgrid_keyboard_actions wxPropertyGrid Action Identifiers
    These are used with wxPropertyGrid::AddActionTrigger() and
    wxPropertyGrid::ClearActionTriggers().
    @{
*/

enum wxPG_KEYBOARD_ACTIONS
{
    wxPG_ACTION_INVALID = 0,
    wxPG_ACTION_NEXT_PROPERTY,
    wxPG_ACTION_PREV_PROPERTY,
    wxPG_ACTION_EXPAND_PROPERTY,
    wxPG_ACTION_COLLAPSE_PROPERTY,
    wxPG_ACTION_CANCEL_EDIT,
    wxPG_ACTION_CUT,
    wxPG_ACTION_COPY,
    wxPG_ACTION_PASTE,
    wxPG_ACTION_MAX
};

/** @}
*/

// -----------------------------------------------------------------------

/** @class wxPropertyGrid

      wxPropertyGrid is a specialized grid for editing properties - in other
    words name = value pairs. List of ready-to-use property classes include
    strings, numbers, flag sets, fonts, colours and many others. It is possible,
    for example, to categorize properties, set up a complete tree-hierarchy,
    add more than two columns, and set arbitrary per-property attributes.

    Please note that most member functions are inherited and as such not
    documented on this page. This means you will probably also want to read
    wxPropertyGridInterface class reference.

    See also @ref overview_propgrid.

    @section propgrid_window_styles_ Window Styles

    See @ref propgrid_window_styles.

    @section propgrid_event_handling Event Handling

    To process input from a property grid control, use these event handler macros
    to direct input to member functions that take a wxPropertyGridEvent argument.

    @beginEventTable{wxPropertyGridEvent}
    @event{EVT_PG_SELECTED (id, func)}
        Respond to wxEVT_PG_SELECTED event, generated when property value
        has been changed by user.
    @event{EVT_PG_CHANGING(id, func)}
        Respond to wxEVT_PG_CHANGING event, generated when property value
        is about to be changed by user. Use wxPropertyGridEvent::GetValue()
        to take a peek at the pending value, and wxPropertyGridEvent::Veto()
        to prevent change from taking place, if necessary.
    @event{EVT_PG_HIGHLIGHTED(id, func)}
        Respond to wxEVT_PG_HIGHLIGHTED event, which occurs when mouse
        moves over a property. Event's property is NULL if hovered area does
        not belong to any property.
    @event{EVT_PG_RIGHT_CLICK(id, func)}
        Respond to wxEVT_PG_RIGHT_CLICK event, which occurs when property is
        clicked on with right mouse button.
    @event{EVT_PG_DOUBLE_CLICK(id, func)}
        Respond to wxEVT_PG_DOUBLE_CLICK event, which occurs when property is
        double-clicked on with left mouse button.
    @event{EVT_PG_ITEM_COLLAPSED(id, func)}
        Respond to wxEVT_PG_ITEM_COLLAPSED event, generated when user collapses
        a property or category.
    @event{EVT_PG_ITEM_EXPANDED(id, func)}
        Respond to wxEVT_PG_ITEM_EXPANDED event, generated when user expands
        a property or category.
    @endEventTable

    @remarks

    - Use Freeze() and Thaw() respectively to disable and enable drawing. This
      will also delay sorting etc. miscellaneous calculations to the last
      possible moment.

    @library{wxpropgrid}
    @category{propgrid}
*/
class wxPropertyGrid : public wxScrolledWindow, public wxPropertyGridInterface
{
public:

	/**
        Two step constructor. Call Create when this constructor is called to
        build up the wxPropertyGrid
	*/
    wxPropertyGrid();

    /**
        Constructor. The styles to be used are styles valid for
        the wxWindow and wxScrolledWindow.

        @see @ref propgrid_window_styles.
    */
    wxPropertyGrid( wxWindow *parent, wxWindowID id = wxID_ANY,
               	    const wxPoint& pos = wxDefaultPosition,
               	    const wxSize& size = wxDefaultSize,
               	    long style = wxPG_DEFAULT_STYLE,
               	    const wxChar* name = wxPropertyGridNameStr );

    /** Destructor */
    virtual ~wxPropertyGrid();

    /**
        Adds given key combination to trigger given action.

        @param action
            Which action to trigger. See @ref propgrid_keyboard_actions.

        @param keycode
            Which keycode triggers the action.

        @param modifiers
            Which key event modifiers, in addition to keycode, are needed to
            trigger the action.
    */
    void AddActionTrigger( int action, int keycode, int modifiers = 0 );

    /**
        This static function enables or disables automatic use of
        wxGetTranslation() for following strings: wxEnumProperty list labels,
        wxFlagsProperty child property labels.

        Default is false.
    */
    static void AutoGetTranslation( bool enable );

    /**
        Changes value of a property, as if from an editor. Use this instead of
        SetPropertyValue() if you need the value to run through validation
        process, and also send the property change event.

        @return Returns true if value was successfully changed.
    */
    bool ChangePropertyValue( wxPGPropArg id, wxVariant newValue );

    /**
        Centers the splitter. If argument is true, automatic splitter centering
        is enabled (only applicable if style wxPG_SPLITTER_AUTO_CENTER was
        defined).
    */
    void CenterSplitter( bool enable_auto_centering = false );

    /**
        Deletes all properties.
    */
    virtual void Clear();

    /**
        Clears action triggers for given action.

        @param action
            Which action to trigger. @ref propgrid_keyboard_actions.
    */
    void ClearActionTriggers( int action );

    /**
        Forces updating the value of property from the editor control.
        Note that wxEVT_PG_CHANGING and wxEVT_PG_CHANGED are dispatched using
        ProcessEvent, meaning your event handlers will be called immediately.

        @return Returns @true if anything was changed.
    */
    virtual bool CommitChangesFromEditor( wxUint32 flags = 0 );

    /**
        Two step creation. Whenever the control is created without any
        parameters, use Create to actually create it. Don't access the control's
        public methods before this is called

        @see @ref propgrid_window_styles.
    */
    bool Create( wxWindow *parent, wxWindowID id = wxID_ANY,
                 const wxPoint& pos = wxDefaultPosition,
                 const wxSize& size = wxDefaultSize,
                 long style = wxPG_DEFAULT_STYLE,
                 const wxChar* name = wxPropertyGridNameStr );

    /**
        Call when editor widget's contents is modified. For example, this is
        called when changes text in wxTextCtrl (used in wxStringProperty and
        wxIntProperty).

        @remarks This function should only be called by custom properties.

        @see wxPGProperty::OnEvent()
    */
    void EditorsValueWasModified() { m_iFlags |= wxPG_FL_VALUE_MODIFIED; }

    /**
        Reverse of EditorsValueWasModified().

        @remarks This function should only be called by custom properties.
    */
    void EditorsValueWasNotModified()
    {
        m_iFlags &= ~(wxPG_FL_VALUE_MODIFIED);
    }

    /**
        Enables or disables (shows/hides) categories according to parameter
        enable.
    */
    bool EnableCategories( bool enable );

    /**
        Scrolls and/or expands items to ensure that the given item is visible.

        @return Returns @true if something was actually done.
    */
    bool EnsureVisible( wxPGPropArg id );

    /**
        Reduces column sizes to minimum possible, while still retaining
        fully visible grid contents (labels, images).

        @return Minimum size for the grid to still display everything.

        @remarks Does not work well with wxPG_SPLITTER_AUTO_CENTER window style.

                This function only works properly if grid size prior to call was
                already fairly large.

                Note that you can also get calculated column widths by calling
                GetState->GetColumnWidth() immediately after this function
                returns.
    */
    wxSize FitColumns();

    /**
        Returns wxWindow that the properties are painted on, and which should be
        used as the parent for editor controls.
    */
    wxPanel* GetPanel() const;

    /**
        Returns current category caption background colour.
    */
    wxColour GetCaptionBackgroundColour() const;

    /**
        Returns current category caption font.
    */
    wxFont& GetCaptionFont();

    /**
        Returns current category caption text colour.
    */
    wxColour GetCaptionForegroundColour() const;

    /**
        Returns current cell background colour.
    */
    wxColour GetCellBackgroundColour() const;

    /**
        Returns current cell text colour when disabled.
    */
    wxColour GetCellDisabledTextColour() const;

    /**
        Returns current cell text colour.
    */
    wxColour GetCellTextColour() const;

    /**
        Returns number of columns currently on grid.
    */
    unsigned int GetColumnCount() const;

    /**
        Returns colour of empty space below properties.
    */
    wxColour GetEmptySpaceColour() const;

    /**
        Returns height of highest characters of used font.
    */
    int GetFontHeight() const;

    /**
        Returns pointer to itself. Dummy function that enables same kind
        of code to use wxPropertyGrid and wxPropertyGridManager.
    */
    wxPropertyGrid* GetGrid();

    /**
        Returns rectangle of custom paint image.

        @param property
            Return image rectangle for this property.

        @param item
            Which choice of property to use (each choice may have
            different image).
    */
    wxRect GetImageRect( wxPGProperty* property, int item ) const;

    /**
        Returns size of the custom paint image in front of property.

        @param property
            Return image rectangle for this property.
            If this argument is NULL, then preferred size is returned.

        @param item
            Which choice of property to use (each choice may have
            different image).
    */
    wxSize GetImageSize( wxPGProperty* property = NULL, int item = -1 ) const;

    /**
        Returns last item which could be iterated using given flags.

        @param flags
            See @ref propgrid_iterator_flags.
    */
    wxPGProperty* GetLastItem( int flags = wxPG_ITERATE_DEFAULT );

    /**
        Returns colour of lines between cells.
    */
    wxColour GetLineColour() const;

    /**
        Returns background colour of margin.
    */
    wxColour GetMarginColour() const;

    /**
        Returns most up-to-date value of selected property. This will return
        value different from GetSelectedProperty()->GetValue() only when text
        editor is activate and string edited by user represents valid,
        uncommitted property value.
    */
    wxVariant GetUncommittedPropertyValue();

    /**
        Returns cell background colour of a property.
    */
    wxColour GetPropertyBackgroundColour( wxPGPropArg id ) const;

    /**
        Returns cell background colour of a property.
    */
    wxColour GetPropertyTextColour( wxPGPropArg id ) const;

    /**
        Returns "root property". It does not have name, etc. and it is not
        visible. It is only useful for accessing its children.
    */
    wxPGProperty* GetRoot() const;

    /**
        Returns height of a single grid row (in pixels).
    */
    int GetRowHeight() const;

    /**
        Returns currently selected property.
    */
    wxPGProperty* GetSelectedProperty() const;

    /**
        Returns currently selected property.
    */
    wxPGProperty* GetSelection() const;

    /**
        Returns current selection background colour.
    */
    wxColour GetSelectionBackgroundColour() const;

    /**
        Returns current selection text colour.
    */
    wxColour GetSelectionForegroundColour() const;

    /**
        Returns current splitter x position.
    */
    int GetSplitterPosition() const;

    /**
        Returns wxTextCtrl active in currently selected property, if any. Takes
        wxOwnerDrawnComboBox into account.
    */
    wxTextCtrl* GetEditorTextCtrl() const;

    /**
        Returns current vertical spacing.
    */
    int GetVerticalSpacing() const { return (int)m_vspacing; }

    /**
        Returns true if editor's value was marked modified.
    */
    bool IsEditorsValueModified() const;

    /**
        Returns information about arbitrary position in the grid.
    */
    wxPropertyGridHitTestResult HitTest( const wxPoint& pt ) const;

    /**
        Returns true if any property has been modified by the user.
    */
    bool IsAnyModified() const;

    /**
        Returns true if updating is frozen (ie. Freeze() called but not
        yet Thaw() ).
    */
    bool IsFrozen() const;

    /**
        Redraws given property.
    */
    virtual void RefreshProperty( wxPGProperty* p );

    /**
        Registers a new editor class.

        @return Returns pointer  to the editor class instance that should be used.
    */
    static wxPGEditor* RegisterEditorClass( wxPGEditor* editor,
                                            const wxString& name,
                                            bool noDefCheck = false );

    /**
        Resets all colours to the original system values.
    */
    void ResetColours();

    /**
        Selects a property. Editor widget is automatically created, but
        not focused unless focus is true. This will generate wxEVT_PG_SELECT
        event.

        @param id
            Property to select (name or pointer).

        @param focus
            If @true, move keyboard focus to the created editor right away.

        @return returns @true if selection finished successfully. Usually only
        fails if current value in editor is not valid.

        @see wxPropertyGrid::ClearSelection()
    */
    bool SelectProperty( wxPGPropArg id, bool focus = false );

    /**
        Changes keyboard shortcut to push the editor button.

        @remarks You can set default with keycode 0. Good value for the platform
                is guessed, but don't expect it to be very accurate.
    */
    void SetButtonShortcut( int keycode, bool ctrlDown = false, bool altDown = false );

    /**
        Sets category caption background colour.
    */
    void SetCaptionBackgroundColour(const wxColour& col);

    /**
        Sets category caption text colour.
    */
    void SetCaptionTextColour(const wxColour& col);

    /**
        Sets default cell background colour - applies to property cells.
        Note that appearance of editor widgets may not be affected.
    */
    void SetCellBackgroundColour(const wxColour& col);

    /**
        Sets cell text colour for disabled properties.
    */
    void SetCellDisabledTextColour(const wxColour& col);

    /**
        Sets default cell text colour - applies to property name and value text.
        Note that appearance of editor widgets may not be affected.
    */
    void SetCellTextColour(const wxColour& col);

    /**
        Set number of columns (2 or more).
    */
    void SetColumnCount( int colCount );

    /**
        Sets the 'current' category - Append will add non-category properties
        under it.
    */
    void SetCurrentCategory( wxPGPropArg id );

    /**
        Sets colour of empty space below properties.
    */
    void SetEmptySpaceColour(const wxColour& col);

    /**
        Sets colour of lines between cells.
    */
    void SetLineColour(const wxColour& col);

    /**
        Sets background colour of margin.
    */
    void SetMarginColour(const wxColour& col);

    /**
        Sets background colour of property and all its children. Colours of
        captions are not affected. Background brush cache is optimized for often
        set colours to be set last.
    */
    void SetPropertyBackgroundColour( wxPGPropArg id, const wxColour& col );

    /**
        Resets text and background colours of given property.
    */
    void SetPropertyColoursToDefault( wxPGPropArg id );

    /**
        Sets text colour of property and all its children.
    */
    void SetPropertyTextColour( wxPGPropArg id, const wxColour& col,
                                bool recursively = true );

    /** Sets selection background colour - applies to selected property name
        background. */
    void SetSelectionBackgroundColour(const wxColour& col);

    /** Sets selection foreground colour - applies to selected property name
        text. */
    void SetSelectionTextColour(const wxColour& col);

    /** Sets x coordinate of the splitter.

        @remarks Splitter position cannot exceed grid size, and therefore setting
                it during form creation may fail as initial grid size is often
                smaller than desired splitter position, especially when sizers
                are being used.
    */
    void SetSplitterPosition( int newxpos, int col = 0 );

    /**
        Moves splitter as left as possible, while still allowing all
        labels to be shown in full.

        @param privateChildrenToo
            If @false, will still allow private children to be cropped.
    */
    void SetSplitterLeft( bool privateChildrenToo = false )
    {
        m_pState->SetSplitterLeft(subProps);
    }

    /**
        Sets vertical spacing. Can be 1, 2, or 3 - a value relative to font
        height. Value of 2 should be default on most platforms.
    */
    void SetVerticalSpacing( int vspacing );

    /**
        Shows an brief error message that is related to a property.
    */
    void ShowPropertyError( wxPGPropArg id, const wxString& msg );

    /**
        Sorts all items at all levels (except private children).
    */
    void Sort();

    /**
        Sorts children of a property.
    */
    void SortChildren( wxPGPropArg id );
};


/**
    @class wxPropertyGridEvent

    A property grid event holds information about events associated with
    wxPropertyGrid objects.

    @library{wxpropgrid}
    @category{propgrid}
*/
class wxPropertyGridEvent : public wxCommandEvent
{
public:

    /** Constructor. */
    wxPropertyGridEvent(wxEventType commandType=0, int id=0);

    /** Copy constructor. */
    wxPropertyGridEvent(const wxPropertyGridEvent& event);

    /** Destructor. */
    ~wxPropertyGridEvent();

    /**
        Returns true if you can veto the action that the event is signaling.
    */
    bool CanVeto() const { return m_canVeto; }

    /** Copyer. */
    virtual wxEvent* Clone() const;

    /**
        Returns highest level non-category, non-root parent of property for
        which event occurred. Useful when you have nested properties with
        children.

        @remarks If immediate parent is root or category, this will return the
                property itself.
    */
    wxPGProperty* GetMainParent() const;

    /**
        Returns property associated with this event.
    */
    wxPGProperty* GetProperty() const;

    /**
        Returns current validation failure flags.
    */
    wxPGVFBFlags GetValidationFailureBehavior() const;

    /**
        Returns value that is about to be set for wxEVT_PG_CHANGING.
    */
    const wxVariant& GetValue() const;

    /**
        Set if event can be vetoed.
    */
    void SetCanVeto( bool canVeto );
    
    /** Changes the property associated with this event. */
    void SetProperty( wxPGProperty* p );

    /**
        Set override validation failure behavior. Only effective if Veto() was
        also called, and only allowed if event type is wxEVT_PG_CHANGING.
    */
    void SetValidationFailureBehavior( wxPGVFBFlags flags );

    /**
        Sets custom failure message for this time only. Only applies if
        wxPG_VFB_SHOW_MESSAGE is set in validation failure flags.
    */
    void SetValidationFailureMessage( const wxString& message );

    /**
        Call this from your event handler to veto action that the event is
        signaling. You can only veto a shutdown if wxPropertyGridEvent::CanVeto()
        returns true.

        @remarks Currently only wxEVT_PG_CHANGING supports vetoing.
    */
    void Veto( bool veto = true );

    /**
        Returns @true if event was vetoed.
    */
    bool WasVetoed() const;
};