docs/latex/wx/custdobj.tex

   1 \section{\class{wxCustomDataObject}}\label{wxcustomdataobject}
   2
   3 wxCustomDataObject is a specialization of
   4 \helpref{wxDataObjectSimple}{wxdataobjectsimple} for some
   5 application-specific data in arbitrary (either custom or one of the standard
   6 ones). The only restriction is that it is supposed that this data can be
   7 copied bitwise (i.e. with {\tt memcpy()}), so it would be a bad idea to make
   8 it contain a C++ object (though C struct is fine).
   9
  10 By default, wxCustomDataObject stores the data inside in a buffer. To put the
  11 data into the buffer you may use either
  12 \helpref{SetData}{wxcustomdataobjectsetdata} or
  13 \helpref{TakeData}{wxcustomdataobjecttakedata} depending on whether you want
  14 the object to make a copy of data or not.
  15
  16 If you already store the data in another place, it may be more convenient and
  17 efficient to provide the data on-demand which is possible too if you override
  18 the virtual functions mentioned below.
  19
  20 \wxheading{Virtual functions to override}
  21
  22 This class may be used as is, but if you don't want store the data inside the
  23 object but provide it on demand instead, you should override
  24 \helpref{GetSize}{wxcustomdataobjectgetsize},
  25 \helpref{GetData}{wxcustomdataobjectgetdata} and
  26 \helpref{SetData}{wxcustomdataobjectsetdata} (or may be only the first two or
  27 only the last one if you only allow reading/writing the data)
  28
  29 \wxheading{Derived from}
  30
  31 \helpref{wxDataObjectSimple}{wxdataobjectsimple}\\
  32 \helpref{wxDataObject}{wxdataobject}
  33
  34 \wxheading{Include files}
  35
  36 <wx/dataobj.h>
  37
  38 \wxheading{See also}
  39
  40 \helpref{wxDataObject}{wxdataobject}
  41
  42 \latexignore{\rtfignore{\wxheading{Members}}}
  43
  44 \membersection{wxCustomDataObject::wxCustomDataObject}\label{wxcustomdataobjectwxcustomdataobject}
  45
  46 \func{}{wxCustomDataObject}{\param{const wxDataFormat\& }{format = wxFormatInvalid}}
  47
  48 The constructor accepts a {\it format} argument which specifies the (single)
  49 format supported by this object. If it isn't set here,
  50 \helpref{SetFormat}{wxdataobjectsimplesetformat} should be used.
  51
  52 \membersection{wxCustomDataObject::\destruct{wxCustomDataObject}}\label{wxcustomdataobjectdtor}
  53
  54 \func{}{\destruct{wxCustomDataObject}}{\void}
  55
  56 The destructor will free the data hold by the object. Notice that although it
  57 calls a virtual \helpref{Free()}{wxcustomdataobjectfree} function, the base
  58 class version will always be called (C++ doesn't allow calling virtual
  59 functions from constructors or destructors), so if you override {\tt Free()}, you
  60 should override the destructor in your class as well (which would probably
  61 just call the derived class' version of {\tt Free()}).
  62
  63 \membersection{wxCustomDataObject::Alloc}\label{wxcustomdataobjectalloc}
  64
  65 \func{virtual void *}{Alloc}{\param{size\_t }{size}}
  66
  67 This function is called to allocate {\it size} bytes of memory from SetData().
  68 The default version just uses the operator new.
  69
  70 \membersection{wxCustomDataObject::Free}\label{wxcustomdataobjectfree}
  71
  72 \func{virtual void}{Free}{\void}
  73
  74 This function is called when the data is freed, you may override it to anything
  75 you want (or may be nothing at all). The default version calls operator
  76 delete$[]$ on the data.
  77
  78 \membersection{wxCustomDataObject::GetSize}\label{wxcustomdataobjectgetsize}
  79
  80 \constfunc{virtual size\_t}{GetSize}{\void}
  81
  82 Returns the data size in bytes.
  83
  84 \membersection{wxCustomDataObject::GetData}\label{wxcustomdataobjectgetdata}
  85
  86 \constfunc{virtual void *}{GetData}{\void}
  87
  88 Returns a pointer to the data.
  89
  90 \membersection{wxCustomDataObject::SetData}\label{wxcustomdataobjectsetdata}
  91
  92 \func{virtual void}{SetData}{
  93  \param{size\_t }{size}, \param{const void }{*data}}
  94
  95 Set the data. The data object will make an internal copy.
  96
  97 \pythonnote{This method expects a string in wxPython.  You can pass
  98 nearly any object by pickling it first.}
  99
 100 \membersection{wxCustomDataObject::TakeData}\label{wxcustomdataobjecttakedata}
 101
 102 \func{virtual void}{TakeData}{
 103  \param{size\_t }{size}, \param{const void }{*data}}
 104
 105 Like \helpref{SetData}{wxcustomdataobjectsetdata}, but doesn't copy the data -
 106 instead the object takes ownership of the pointer.
 107
 108 \pythonnote{This method expects a string in wxPython.  You can pass
 109 nearly any object by pickling it first.}
 110