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%% Name: tclipbrd.tex
%% Purpose: Data transfer (clipboard and drag and drop) overview
%% Author: Vadim Zeitlin
%% RCS-ID: $Id$
%% Copyright: (c) Vadim Zeitlin
%% Licence: wxWindows licence
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-\section{Clipboard and drag and drop overview}\label{wxclipboardonfigoverview}
+\section{Clipboard and drag and drop overview}\label{wxdndoverview}
Classes: \helpref{wxDataObject}{wxdataobject},
- \helpref{wxClipboard}{wxclipboard},
- \helpref{wxDataFormat}{wxdataformat},
- \helpref{wxDropSource}{wxdropsource},
- \helpref{wxDropTarget}{wxdroptarget}
+ \helpref{wxClipboard}{wxclipboard},
+ \helpref{wxDataFormat}{wxdataformat},
+ \helpref{wxDropSource}{wxdropsource},
+ \helpref{wxDropTarget}{wxdroptarget}
+
+See also: \helpref{DnD sample}{samplednd}
This overview discusses data transfer through clipboard or drag and drop. In
wxWindows, these two ways to transfer data (either between different
applications or inside one and the same) are very similar which allows to
-implement both of them using almost the same code - or, to say it in other
+implement both of them using almost the same code - or, in other
words, if you implement drag and drop support for your application, you get
clipboard support for free and vice versa.
-In the heart of both clipboard and drag and drop operations lies the
-\helpref{wxDataObject}{wxdataobject} class. The objects of this (or, to be
-precise, derived from it) class represent the data which is being carried by
-the mouse during drag and drop operation or copied to or pasted from the
-clipboard. \helpref{wxDataObject}{wxdataobject} is a "smart" piece of data
-because it knows which \helpref{formats}{wxdataformat} it supports (see
-\helpref{GetFormatCount}{wxdataobjectgetformatcount} and
-\helpref{GetAllFormats}{wxdataobjectgetallformats}) and knows how to render
-itself in any of them (see \helpref{GetDataHere.}{wxdataobjectgetdatahere}).
-It can also receive its value from the outside in a format it supports if it
-implements \helpref{SetData}{wxdataobjectsetdata} method.
+At the heart of both clipboard and drag and drop operations lies the
+\helpref{wxDataObject}{wxdataobject} class. The objects of this class (or, to
+be precise, classes derived from it) represent the data which is being carried
+by the mouse during drag and drop operation or copied to or pasted from the
+clipboard. wxDataObject is a "smart" piece of data because it knows which
+formats it supports (see GetFormatCount and GetAllFormats) and knows how to
+render itself in any of them (see GetDataHere). It can also receive its value
+from the outside in a format it supports if it implements the SetData method.
+Please see the documentation of this class for more details.
Both clipboard and drag and drop operations have two sides: the source and
-target, the data provider and the data receiver (which may be the same
+target, the data provider and the data receiver. These which may be in the same
application and even the same window when, for example, you drag some text from
-one position to another in a word processor). Let us describe what each of them
+one position to another in a word processor. Let us describe what each of them
should do.
-\subsection{The data provider (source) duties}{wxdataobjectsource}
+\subsection{The data provider (source) duties}\label{wxdataobjectsource}
The data provider is responsible for creating a
-\helpref{wxDataObject}{wxdataobjectwxdataobject} containing the data to be
-transfered. Then it should either pass it to the clipboard using
-\helpref{AddData}{wxclipboardadddata} or \helpref{SetData}{wxclipboardsetdata}
-functions or to \helpref{wxDropSource}{wxdropsource} and call
+\helpref{wxDataObject}{wxdataobject} containing the data to be
+transfered. Then it should either pass it to the clipboard using
+\helpref{SetData}{wxclipboardsetdata} function or to
+\helpref{wxDropSource}{wxdropsource} and call
\helpref{DoDragDrop}{wxdropsourcedodragdrop} function.
The only (but important) difference is that the object for the clipboard
afterwards and so can be created either on heap or on stack (i.e. as a local
variable).
-Another small difference si that in the case of clipboard operation, the
+Another small difference is that in the case of clipboard operation, the
application usually knows in advance whether it copies or cuts (i.e. copies and
deletes) data - in fact, this usually depends on which menu item the user
chose. But for drag and drop it can only know it after
\helpref{DoDragDrop}{wxdropsourcedodragdrop} returns (from its return value).
-\subsection{The data receiver (target) duties}{wxdataobjecttarget}
+\subsection{The data receiver (target) duties}\label{wxdataobjecttarget}
To receive (paste in usual terminology) data from the clipboard, you should
create a \helpref{wxDataObject}{wxdataobject} derived class which supports the
no data in (any of) the supported format(s) is available. If it returns {\tt
TRUE}, the data has been successfully transfered to wxDataObject.
-{\bf TODO} document drag and drop side when the API is finalised
+For drag and drop case, the \helpref{wxDropTarget::OnData}{wxdroptargetondata}
+virtual function will be called when a data object is dropped, from which the
+data itself may be requested by calling
+\helpref{wxDropTarget::GetData}{wxdroptargetwxdroptarget} method which fills
+the data object.
+
projects / wxWidgets.git / blobdiff