@page overview_dataobject wxDataObject Overview
-Classes: wxDataObject, wxClipboard, wxDataFormat, wxDropSource, wxDropTarget
+@tableofcontents
-See also: @ref overview_dnd and @ref page_samples_dnd
-
-This overview discusses data transfer through clipboard or drag and drop.
-In wxWidgets, these two ways to transfer data (either between different
+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.
+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
-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.
+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. These which may be in the same
one position to another in a word processor. Let us describe what each of them
should do.
-@li @ref overview_dataobject_source
-@li @ref overview_dataobject_target
-
+@see @ref overview_dnd, @ref group_class_dnd, @ref page_samples_dnd
-<hr>
-@section overview_dataobject_source The data provider (source) duties
+@section overview_dataobject_source The Data Provider (Source)
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
-wxClipboard::SetData function or to wxDropSource and call wxDropSource::DoDragDrop
-function.
+wxClipboard::SetData function or to wxDropSource and call
+wxDropSource::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
+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
wxDropSource::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
-wxDropSource::DoDragDrop returns (from its return value).
+chose. But for drag and drop it can only know it after wxDropSource::DoDragDrop
+returns (from its return value).
-@section overview_dataobject_target The data receiver (target) duties
+
+@section overview_dataobject_target The Data Receiver (Target)
To receive (paste in usual terminology) data from the clipboard, you should
create a wxDataObject derived class which supports the data formats you need
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.
+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.
*/
-
projects / wxWidgets.git / blobdiff