/////////////////////////////////////////////////////////////////////////////
-// Name: dataobject
+// Name: dataobject.h
// Purpose: topic overview
// Author: wxWidgets team
// RCS-ID: $Id$
/////////////////////////////////////////////////////////////////////////////
/*!
-
- @page dataobject_overview wxDataObject overview
-
- Classes: #wxDataObject,
- #wxClipboard,
- #wxDataFormat,
- #wxDropSource,
- #wxDropTarget
- See also: @ref dnd_overview and @ref samplednd_overview
- This overview discusses data transfer through clipboard or drag and drop. In
- wxWidgets, these two ways to transfer data (either between different
+
+ @page overview_dataobject wxDataObject overview
+
+ Classes: #wxDataObject, #wxClipboard, #wxDataFormat, #wxDropSource, #wxDropTarget
+
+ See also: @ref overview_dnd and @ref overview_samplednd
+
+ This overview discusses data transfer through clipboard or drag and drop.
+ In wxWidgets, 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, in other
words, if you implement drag and drop support for your application, you get
clipboard support for free and vice versa.
- At the heart of both clipboard and drag and drop operations lies the
+
+ At the heart of both clipboard and drag and drop operations lies the
#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
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. 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
should do.
- #The data provider (source) duties
- #The data receiver (target) duties
-
-
- @section wxdataobjectsource The data provider (source) duties
-
- The data provider is responsible for creating a
- #wxDataObject containing the data to be
- transferred. Then it should either pass it to the clipboard using
- #SetData function or to
- #wxDropSource and call
- #DoDragDrop function.
+
+ @li The data provider (source) duties
+ @li The data receiver (target) duties
+
+
+ @section overview_dataobject_source The data provider (source) duties
+
+ The data provider is responsible for creating a #wxDataObject containing the
+ data to be transferred. Then it should either pass it to the clipboard using
+ #SetData function or to #wxDropSource and call #DoDragDrop function.
+
The only (but important) difference is that the object for the clipboard
transfer must always be created on the heap (i.e. using @c new) and it will
be freed by the clipboard when it is no longer needed (indeed, it is not known
in advance when, if ever, the data will be pasted from the clipboard). On the
- other hand, the object for drag and drop operation must only exist while
- #DoDragDrop executes and may be safely deleted
- afterwards and so can be created either on heap or on stack (i.e. as a local
- variable).
+ other hand, the object for drag and drop operation must only exist while
+ #DoDragDrop executes and may be safely deleted afterwards and so can be
+ created either on heap or on stack (i.e. as a local variable).
+
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
+ chose. But for drag and drop it can only know it after
#DoDragDrop returns (from its return value).
-
- @section wxdataobjecttarget The data receiver (target) duties
-
+
+
+ @section overview_dataobject_target The data receiver (target) duties
+
To receive (paste in usual terminology) data from the clipboard, you should
- create a #wxDataObject derived class which supports the
- data formats you need and pass it as argument to
- wxClipboard::GetData. If it returns @false,
- no data in (any of) the supported format(s) is available. If it returns @true, the data has been successfully transferred to wxDataObject.
- For drag and drop case, the wxDropTarget::OnData
- virtual function will be called when a data object is dropped, from which the
- data itself may be requested by calling
- wxDropTarget::GetData method which fills
- the data object.
-
- */
-
-
+ create a #wxDataObject derived class which supports the data formats you need
+ and pass it as argument to wxClipboard::GetData. If it returns @false,
+
+ no data in (any of) the supported format(s) is available. If it returns @true,
+ the data has been successfully transferred to wxDataObject.
+
+ For drag and drop case, the wxDropTarget::OnData virtual function will be called
+ when a data object is dropped, from which the data itself may be requested by calling
+ wxDropTarget::GetData method which fills the data object.
+
+*/
+
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