How to find out a MIMETYPE of anCustomWidget(QWidget)?

Hi
I have two scene, which top scene has some pixmaps(by now there is only gauge but later i want use for example some graphs). every pixmap is image of a QWidget. i want to whenever user drag a pixmap into bottom scene a custom Qwidget will create there. I want to do that by mimedata but i don't know which type it is

here is a snapshot

Attachment 7464

the mime type is the one you set in the QDrag object when the drag started.
Have a look at the QDrag class documentation.