<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Drag and Drop</title> <link rel="stylesheet" href="style.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.75.1"> <link rel="home" href="index.html" title="Programming with gtkmm"> <link rel="up" href="chapter-treeview.html" title="Chapter 8. The TreeView widget"> <link rel="prev" href="sec-treeview-sort.html" title="Sorting"> <link rel="next" href="sec-treeview-contextmenu.html" title="Popup Context Menu"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr><th colspan="3" align="center">Drag and Drop</th></tr> <tr> <td width="20%" align="left"> <a accesskey="p" href="sec-treeview-sort.html"><img src="icons/prev.png" alt="Prev"></a> </td> <th width="60%" align="center">Chapter 8. The TreeView widget</th> <td width="20%" align="right"> <a accesskey="n" href="sec-treeview-contextmenu.html"><img src="icons/next.png" alt="Next"></a> </td> </tr> </table> <hr> </div> <div class="sect1" title="Drag and Drop"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="sec-treeview-draganddrop"></a>Drag and Drop</h2></div></div></div> <p> <code class="classname">Gtk::TreeView</code> already implments simple drag-and-drop when used with the <code class="classname">Gtk::ListStore</code> or <code class="classname">Gtk::TreeStore</code> models. If necessary, it also allows you to implement more complex behaviour when items are dragged and dropped, using the normal <a class="link" href="chapter-draganddrop.html" title="Chapter 16. Drag and Drop">Drag and Drop</a> API. </p> <div class="sect2" title="Reorderable rows"> <div class="titlepage"><div><div><h3 class="title"> <a name="treeview-reorderable-rows"></a>Reorderable rows</h3></div></div></div> <p> If you call <code class="methodname">Gtk::TreeView::set_reorderable()</code> then your TreeView's items can be moved within the treeview itself. This is demonstrated in the <code class="classname">TreeStore</code> example. </p> <p>However, this does not allow you any control of which items can be dragged, and where they can be dropped. If you need that extra control then you might create a derived <code class="literal">Gtk::TreeModel</code> from <code class="literal">Gtk::TreeStore</code> or <code class="literal">Gtk::ListStore</code> and override the <code class="literal">Gtk::TreeDragSource::row_draggable()</code> and <code class="literal">Gdk::TreeDragDest::row_drop_possible()</code> virtual methods. You can examine the <code class="literal">Gtk::TreeModel::Path</code>s provided and allow or disallow dragging or dropping by return <code class="literal">true</code> or <code class="literal">false</code>.</p> <p>This is demonstrated in the drag_and_drop example.</p> </div> </div> <div class="navfooter"> <hr> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"> <a accesskey="p" href="sec-treeview-sort.html"><img src="icons/prev.png" alt="Prev"></a> </td> <td width="20%" align="center"><a accesskey="u" href="chapter-treeview.html"><img src="icons/up.png" alt="Up"></a></td> <td width="40%" align="right"> <a accesskey="n" href="sec-treeview-contextmenu.html"><img src="icons/next.png" alt="Next"></a> </td> </tr> <tr> <td width="40%" align="left" valign="top">Sorting </td> <td width="20%" align="center"><a accesskey="h" href="index.html"><img src="icons/home.png" alt="Home"></a></td> <td width="40%" align="right" valign="top"> Popup Context Menu</td> </tr> </table> </div> </body> </html>
