X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/330d6fd06384c6a49d72696cb1da012bbb978132..80d2803f703d1b238f42725504f08266ef02defe:/docs/latex/wx/tdnd.tex?ds=sidebyside diff --git a/docs/latex/wx/tdnd.tex b/docs/latex/wx/tdnd.tex index a2a970a951..3f57d7ab24 100644 --- a/docs/latex/wx/tdnd.tex +++ b/docs/latex/wx/tdnd.tex @@ -1,4 +1,4 @@ -\section{Drag-and-drop and clipboard overview}\label{wxdndoverview} +\section{Drag and drop overview}\label{wxdndoverview} Classes: \helpref{wxDataObject}{wxdataobject}, \helpref{wxTextDataObject}{wxtextdataobject}, @@ -8,55 +8,53 @@ Classes: \helpref{wxDataObject}{wxdataobject}, \helpref{wxFileDropTarget}{wxfiledroptarget} Note that wxUSE\_DRAG\_AND\_DROP must be defined in setup.h in order -to use Drag'n'Drop in wxWindows. +to use drag and drop in wxWindows. -This overview describes wxWindows support for drag and drop and clipboard -operations. Both of these topics are discussed here because, in fact, they're -quite related. Drag and drop and clipboard are just two ways of passing the -data around and so the code required to implement both types of the operations -is almost the same. +See also: \helpref{wxDataObject overview}{wxdataobjectoverview} and \helpref{DnD sample}{samplednd} -Both operations involve passing some data from one program to another, -although the data can be received in the same program as the source. In the case -of clipboard transfer, the data is first placed on the clipboard and then -pasted into the destination program, while for a drag-and-drop operation the -data object is not stored anywhere but is created when the user starts -dragging and is destroyed as soon as he ends it, whether the operation was -ended successfully or cancelled. +It may be noted that data transfer to and from the clipboard is quite +similar to data transfer with drag and drop and the code to implement +these two types is almost the same. In particular, both data transfer +mechanisms store data in some kind of \helpref{wxDataObject}{wxdataobject} +and identify its format(s) using the \helpref{wxDataFormat}{wxdataformat} +class. To be a {\it drag source}, i.e. to provide the data which may be dragged by user elsewhere, you should implement the following steps: \begin{itemize}\itemsep=0pt -\item {\bf Preparation:} First of all, the data object must be created and +\item {\bf Preparation:} First of all, a data object must be created and initialized with the data you wish to drag. For example: \begin{verbatim} - wxDataObject *my_data = new wxTextDataObject data("This string will be dragged."); + wxTextDataObject my_data("This text will be dragged."); \end{verbatim} \item{\bf Drag start:} To start dragging process (typically in response to a -mouse click) you must call \helpref{DoDragDrop}{wxdropsourcedodragdrop} function -of wxDropSource object which should be constructed like this: +mouse click) you must call \helpref{wxDropSource::DoDragDrop}{wxdropsourcedodragdrop} +like this: \begin{verbatim} wxDropSource dragSource( this ); dragSource.SetData( my_data ); + wxDragResult result = dragSource.DoDragDrop( TRUE ); \end{verbatim} -\item {\bf Dragging:} The call to DoDragDrop() blocks until the user release the +\item {\bf Dragging:} The call to DoDragDrop() blocks the program until the user release the mouse button (unless you override \helpref{GiveFeedback}{wxdropsourcegivefeedback} function to do something special). When the mouse moves in a window of a program which understands the same drag-and-drop protocol (any program under Windows or any program supporting the XDnD protocol under X Windows), the corresponding \helpref{wxDropTarget}{wxdroptarget} methods are called - see below. \item {\bf Processing the result:} DoDragDrop() returns an {\it effect code} which -is one of the values of \helpref{wxDragResult}{wxdropsource} enum. Codes -of wxDragError, wxDragNone and wxDragCancel have the obvious meaning and mean -that there is nothing to do on the sending end (except of possibly logging the -error in the first case). wxDragCopy means that the data has been successfully -copied and doesn't require any specific actions neither. But wxDragMove is -special because it means that the data must be deleted from where it was -copied. If it doesn't make sense (dragging selected text from a read-only -file) you should pass FALSE as parameter to DoDragDrop() in the previous step. +is one of the values of {\tt wxDragResult} enum (explained \helpref{here}{wxdroptarget}): + +\begin{verbatim} + switch (result) + { + case wxDragCopy: /* copy the data */ break; + case wxDragMove: /* move the data */ break; + default: /* do nothing */ break; + } +\end{verbatim} \end{itemize} To be a {\it drop target}, i.e. to receive the data dropped by user you should