wxCommand Class Reference

#include <wx/cmdproc.h>

Inheritance diagram for wxCommand:

Detailed Description

wxCommand is a base class for modelling an application command, which is an action usually performed by selecting a menu item, pressing a toolbar button or any other means provided by the application to change the data or view.

Library:  wxCore

Category:  Document/View Framework

See also

wxCommand Overview

Public Member Functions
	wxCommand (bool canUndo=false, const wxString &name=wxEmptyString)
	Constructor. More...
virtual	~wxCommand ()
	Destructor. More...
virtual bool	CanUndo () const
	Returns true if the command can be undone, false otherwise. More...
virtual bool	Do ()=0
	Override this member function to execute the appropriate action when called. More...
virtual wxString	GetName () const
	Returns the command name. More...
virtual bool	Undo ()=0
	Override this member function to un-execute a previous Do. More...
Public Member Functions inherited from wxObject
	wxObject ()
	Default ctor; initializes to NULL the internal reference data. More...
	wxObject (const wxObject &other)
	Copy ctor. More...
virtual	~wxObject ()
	Destructor. More...
virtual wxClassInfo *	GetClassInfo () const
	This virtual function is redefined for every class that requires run-time type information, when using the wxDECLARE_CLASS macro (or similar). More...
wxObjectRefData *	GetRefData () const
	Returns the wxObject::m_refData pointer, i.e. the data referenced by this object. More...
bool	IsKindOf (const wxClassInfo *info) const
	Determines whether this class is a subclass of (or the same class as) the given class. More...
bool	IsSameAs (const wxObject &obj) const
	Returns true if this object has the same data pointer as obj. More...
void	Ref (const wxObject &clone)
	Makes this object refer to the data in clone. More...
void	SetRefData (wxObjectRefData *data)
	Sets the wxObject::m_refData pointer. More...
void	UnRef ()
	Decrements the reference count in the associated data, and if it is zero, deletes the data. More...
void	UnShare ()
	This is the same of AllocExclusive() but this method is public. More...
void	operator delete (void *buf)
	The delete operator is defined for debugging versions of the library only, when the identifier __WXDEBUG__ is defined. More...
void *	operator new (size_t size, const wxString &filename=NULL, int lineNum=0)
	The new operator is defined for debugging versions of the library only, when the identifier __WXDEBUG__ is defined. More...

Additional Inherited Members
Protected Member Functions inherited from wxObject
void	AllocExclusive ()
	Ensure that this object's data is not shared with any other object. More...
virtual wxObjectRefData *	CreateRefData () const
	Creates a new instance of the wxObjectRefData-derived class specific to this object and returns it. More...
virtual wxObjectRefData *	CloneRefData (const wxObjectRefData *data) const
	Creates a new instance of the wxObjectRefData-derived class specific to this object and initializes it copying data. More...
Protected Attributes inherited from wxObject
wxObjectRefData *	m_refData
	Pointer to an object which is the object's reference-counted data. More...

Constructor & Destructor Documentation

wxCommand()

wxCommand::wxCommand	(	bool	canUndo = false,
		const wxString &	name = wxEmptyString
	)

Constructor.

wxCommand is an abstract class, so you will need to derive a new class and call this constructor from your own constructor.

Parameters

canUndo	Tells the command processor whether this command is undo-able. You can achieve the same functionality by overriding the CanUndo() member function (if for example the criteria for undoability is context-dependent).
name	Must be supplied for the command processor to display the command name in the application's edit menu.

~wxCommand()

virtual wxCommand::~wxCommand ( )

virtual

Destructor.

Member Function Documentation

CanUndo()

virtual bool wxCommand::CanUndo ( ) const

virtual

Returns true if the command can be undone, false otherwise.

Do()

virtual bool wxCommand::Do ( )

pure virtual

Override this member function to execute the appropriate action when called.

Returns

true to indicate that the action has taken place, false otherwise. Returning false will indicate to the command processor that the action is not undoable and should not be added to the command history.

Implemented in wxRichTextCommand.

GetName()

virtual wxString wxCommand::GetName ( ) const

virtual

Returns the command name.

Undo()

virtual bool wxCommand::Undo ( )

pure virtual

Override this member function to un-execute a previous Do.

How you implement this command is totally application dependent, but typical strategies include:

• Perform an inverse operation on the last modified piece of data in the document. When redone, a copy of data stored in command is pasted back or some operation reapplied. This relies on the fact that you know the ordering of Undos; the user can never Undo at an arbitrary position in the command history.
• Restore the entire document state (perhaps using document transacting). Potentially very inefficient, but possibly easier to code if the user interface and data are complex, and an "inverse execute" operation is hard to write. The docview sample uses the first method, to remove or restore segments in the drawing.

Returns

true to indicate that the action has taken place, false otherwise. Returning false will indicate to the command processor that the action is not redoable and no change should be made to the command history.

Implemented in wxRichTextCommand.