The thing is: It would be very useful to "drag" a class from
a user control and "drop" that class into another user control.

For example, if my case I am building a sound app, ant it would be
useful to have a tree for exploring the sounds and a list with the
props of a sound being dropped into it.

They way I may implemnt it is:

To have a global var such as "Global DraggedSound as CSound"
and set a reference to the sound I wish to "send" into the global
reference instead of passing the data within the DataObject, and
use this reference instead of the data in the dataobject. I would
also send "somenthing" dummy into the dataobject to raise
the events in the proper order.

The thing is... Is this correct? I mean, for example it will not
work into a cross-application environment, and perhaps there is
a better solution than this dirty trick.

Any suggestions are welcome.

Aside from using an object to wrap up the drag-n-drop functionality
instead of a global variable, I did the exact same thing you did.
If you'd like a more 'proper' way of doing it, you need to use the
functions along the lines of RegisterClipboardType (or something
similar) and create your own clipboard datatype and then use that
with the dataobject.  Unless cross-application is important to you
I wouldn't bother.

Tom