Drag and drop mysteries

[Matthias Kaeppler <nospam digitalraid com>]

Hello,

I want to implement drag and drop for my filemanager application. I have 
two treeviews of the filesystem, now I want to be able to drag e.g. a 
file from the left to right, but the drag and drop mechanics in gtkmm 
are a complete mystery to me, and the documentation is not very giving 
in this part.

Okay, first question would be:
Where comes this TargetEntry class into play? I don't get what I have to 
specify there. The examples in the documentation are rather odd and 
pretty meaningless to me (what are "STRING" and "text/plain" supposed to 
be?).

Say I want to separate between dragging directories and files, would I 
then have to create two TargetEntries, one called "dir" and the other 
called "file", for example, or what?

Furthermore, although I have set my treeview widget to be both 
destination and source for dnd events, it never accepts any "drops", at 
least not visually (the dragged entry always "flies back" to the source 
widget).

How come?

And what are the singal_drag_data_get and signal_drag_data_received 
events and when are they fired?

So many questions :)

Here is some code, I don't know if it's sane or not...

    // enable drag and drop
    m_target_entries.push_back( Gtk::TargetEntry("FILE") );
    m_target_entries.push_back( Gtk::TargetEntry("DIR") );

    m_view.drag_source_set( m_target_entries );
    m_view.drag_dest_set(
	m_target_entries,
	Gtk::DEST_DEFAULT_ALL,
	Gdk::DragAction( GDK_ACTION_COPY | GDK_ACTION_MOVE | GDK_ACTION_LINK )
	);

    m_view.signal_drag_data_received()
	.connect( sigc::mem_fun( *this, &DirBrowser::on_drag_data_received ) );


The event is never fired when I drag around things.

--
Matthias Kaeppler