0a2017e01e
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4388 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
108 lines
4.0 KiB
TeX
108 lines
4.0 KiB
TeX
\section{\class{wxCustomDataObject}}\label{wxcustomdataobject}
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wxCustomDataObject is a specialization of
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\helpref{wxDataObjectSimple}{wxdataobjectsimple} for some
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application-specific data in arbitrary (either custom or one of the standard
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ones). The only restriction is that it is supposed that this data can be
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copied bitwise (i.e. with {\tt memcpy()}), so it would be a bad idea to make
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it contain a C++ object (though C struct is fine).
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By default, wxCustomDataObject stores the data inside in a buffer. To put the
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data into the buffer you may use either
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\helpref{SetData}{wxcustomdataobjectsetdata} or
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\helpref{TakeData}{wxcustomdataobjecttakedata} depending on whether you want
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the object to make a copy of data or not.
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If you already store the data in another place, it may be more convenient and
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efficient to provide the data on-demand which is possible too if you override
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the virtual functions mentioned below.
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\wxheading{Virtual functions to override}
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This class may be used as is, but if you don't want store the data inside the
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object but provide it on demand instead, you should override
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\helpref{GetSize}{wxcustomdataobjectgetsize},
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\helpref{GetData}{wxcustomdataobjectgetdata} and
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\helpref{SetData}{wxcustomdataobjectsetdata} (or may be only the first two or
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only the last one if you only allow reading/writing the data)
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\wxheading{Derived from}
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\helpref{wxDataObjectSimple}{wxdataobjectsimple}\\
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\helpref{wxDataObject}{wxdataobject}
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\wxheading{Include files}
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<wx/dataobj.h>
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\wxheading{See also}
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\helpref{wxDataObject}{wxdataobject}
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\latexignore{\rtfignore{\wxheading{Members}}}
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\membersection{wxCustomDataObject::wxCustomDataObject}\label{wxcustomdataobjectwxcustomdataobject}
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\func{}{wxCustomDataObject}{\param{const wxDataFormat\& }{format = wxFormatInvalid}}
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The constructor accepts a {\it format} argument which specifies the (single)
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format supported by this object. If it isn't set here,
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\helpref{SetFormat}{wxdataobjectsimplesetformat} should be used.
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\membersection{wxCustomDataObject::\destruct{wxCustomDataObject}}\label{wxcustomdataobjectdtor}
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\func{}{\destruct{wxCustomDataObject}}{\void}
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The destructor will free the data hold by the object. Notice that although it
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calls a virtual \helpref{Free()}{wxcustomdataobjectfree} function, the base
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class version will always be called (C++ doesn't allow calling virtual
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functions from constructors or destructors), so if you override {\tt Free()}, you
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should override the destructor in your class as well (which would probably
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just call the derived class' version of {\tt Free()}).
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\membersection{wxCustomDataObject::Alloc}\label{wxcustomdataobjectalloc}
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\func{virtual void *}{Alloc}{\param{size\_t }{size}}
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This function is called to allocate {\it size} bytes of memory from SetData().
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The default version just uses the operator new.
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\membersection{wxCustomDataObject::Free}\label{wxcustomdataobjectfree}
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\pythonnote{This method expects a string in wxPython. You can pass
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nearly any object by pickling it first.}
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\func{virtual void}{Free}{\void}
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This function is called when the data is freed, you may override it to anything
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you want (or may be nothing at all). The default version calls operator
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delete$[]$ on the data.
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\membersection{wxCustomDataObject::GetSize}\label{wxcustomdataobjectgetsize}
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\constfunc{virtual size\_t}{GetSize}{\void}
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Returns the data size in bytes.
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\membersection{wxCustomDataObject::GetData}\label{wxcustomdataobjectgetdata}
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\constfunc{virtual void *}{GetData}{\void}
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Returns a pointer to the data.
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\membersection{wxCustomDataObject::SetData}\label{wxcustomdataobjectsetdata}
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\func{virtual void}{SetData}{
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\param{size\_t }{size}, \param{const void }{*data}}
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Set the data. The data object will make an internal copy.
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\membersection{wxCustomDataObject::TakeData}\label{wxcustomdataobjecttakedata}
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\func{virtual void}{TakeData}{
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\param{size\_t }{size}, \param{const void }{*data}}
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Like \helpref{SetData}{wxcustomdataobjectsetdata}, but doesn't copy the data -
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instead the object takes ownership of the pointer.
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