.\" This is a wxWidgets manpage page generated from the XML docs
.TH wxCommand 3wx 2005-02-15 "wxWidgets" "wxWidgets class documentation"
.SH NAME
wxCommand \- 
.SH 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.
  
 
.SH "PARENTS"

  wxObject
 
.SH "INCLUDE FILES"
wx/cmdproc.h
.SH MEMBERS

  
.SS  wxCommand (bool canUndo = falseconst wxString& name = NULL)

     


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


      
       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.
     
    
   
  
.SS  ~wxCommand ()

     


      Destructor.
     
    
   
  
.SS bool CanUndo ()

     


      Returns true if the command can be undone, false otherwise.
     
    
   
  
.SS bool Do ()

     


      Override this member function to execute the appropriate action when
      called. Return 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.
     
    
   
  
.SS wxString GetName ()

     


      Returns the command name.
     
    
   
  
.SS bool Undo ()

     


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


      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 transactioning).
        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.
     
    
 
.SH "SEE ALSO"

  wxObject
 
  Overview
 
.SH "AUTHORS"
Documentation content by Julian Smart, Robert Roebling, Vadim Zeitlin, Robin Dunn, et al

Conversion to manpage format by Arnout Engelen (http://bzzt.net), bugreports welcome.