NAME

       wxDataObject - Functions for wxDataObject class

DESCRIPTION

       A wxDataObject represents data that can be copied to or from the clipboard, or dragged and
       dropped. The important thing about wxDataObject is that this is a 'smart'  piece  of  data
       unlike  'dumb'  data  containers such as memory buffers or files. Being 'smart' here means
       that the data object itself should know what data formats it supports and  how  to  render
       itself in each of its supported formats.

       A supported format, incidentally, is exactly the format in which the data can be requested
       from a data object or from which the data object may be  set.  In  the  general  case,  an
       object  may  support  different  formats  on  'input' and 'output', i.e. it may be able to
       render itself in a given format but not be created from data on this format or vice versa.
       wxDataObject  defines the wxDataObject::Direction (not implemented in wx) enumeration type
       which distinguishes between them.

       See wxDataFormat (not implemented in wx) documentation for more about formats.

       Not surprisingly, being 'smart' comes at a price of added complexity. This  is  reasonable
       for  the  situations when you really need to support multiple formats, but may be annoying
       if you only want to do something simple like cut and paste text.

       To provide a solution for both cases, wxWidgets has two predefined  classes  which  derive
       from  wxDataObject:  wxDataObjectSimple  (not implemented in wx) and wxDataObjectComposite
       (not implemented in wx). wxDataObjectSimple  (not  implemented  in  wx)  is  the  simplest
       wxDataObject  possible  and  only holds data in a single format (such as HTML or text) and
       wxDataObjectComposite (not  implemented  in  wx)  is  the  simplest  way  to  implement  a
       wxDataObject that does support multiple formats because it achieves this by simply holding
       several wxDataObjectSimple (not implemented in wx) objects.

       So, you have several solutions when you need a wxDataObject class (and  you  need  one  as
       soon as you want to transfer data via the clipboard or drag and drop):

       Please  note  that  the  easiest  way to use drag and drop and the clipboard with multiple
       formats is by using wxDataObjectComposite (not implemented in wx), but it is not the  most
       efficient  one  as each wxDataObjectSimple (not implemented in wx) would contain the whole
       data in its respective formats. Now imagine that you want to paste 200 pages  of  text  in
       your  proprietary  format,  as  well  as  Word,  RTF,  HTML, Unicode and plain text to the
       clipboard and even today's computers are in trouble. For  this  case,  you  will  have  to
       derive  from  wxDataObject directly and make it enumerate its formats and provide the data
       in the requested format on demand.

       Note that neither the GTK+ data transfer mechanisms for clipboard and drag and  drop,  nor
       OLE  data  transfer, copies any data until another application actually requests the data.
       This is in contrast to the 'feel' offered to the user of  a  program  who  would  normally
       think  that  the data resides in the clipboard after having pressed 'Copy' - in reality it
       is only declared to be available.

       You may also derive your own data object classes from wxCustomDataObject (not  implemented
       in  wx)  for  user-defined  types. The format of user-defined data is given as a mime-type
       string literal, such as "application/word" or "image/png". These strings are used as  they
       are  under  Unix  (so  far  only  GTK+) to identify a format and are translated into their
       Windows equivalent under Win32 (using the OLE IDataObject for data exchange  to  and  from
       the  clipboard  and  for  drag  and  drop).  Note that the format string translation under
       Windows is not yet finished.

       Each class derived directly from wxDataObject must  override  and  implement  all  of  its
       functions  which  are  pure  virtual in the base class. The data objects which only render
       their data or only set it (i.e.  work  in  only  one  direction),  should  return  0  from
       GetFormatCount() (not implemented in wx).

       See:  Overview  dnd,  Examples,  wxFileDataObject,  wxTextDataObject,  wxBitmapDataObject,
       wxCustomDataObject  (not  implemented  in  wx),  wxDropTarget  (not  implemented  in  wx),
       wxDropSource   (not   implemented  in  wx),  wxTextDropTarget  (not  implemented  in  wx),
       wxFileDropTarget (not implemented in wx)

       wxWidgets docs: wxDataObject

DATA TYPES

       wxDataObject() = wx:wx_object()