# `tkinter.dnd` — Drag and drop support

Source code: Lib/tkinter/dnd.py

Note

This is experimental and due to be deprecated when it is replaced with the Tk DND.

The `tkinter.dnd` module provides drag-and-drop support for objects within a single application, within the same window or between windows. To enable an object to be dragged, you must create an event binding for it that starts the drag-and-drop process. Typically, you bind a ButtonPress event to a callback function that you write (see Bindings and events). The function should call `dnd_start()`, where ‘source’ is the object to be dragged, and ‘event’ is the event that invoked the call (the argument to your callback function).

Selection of a target object occurs as follows:

1. Top-down search of area under mouse for target widget

> - Target widget should have a callable dnd_accept attribute

> - If dnd_accept is not present or returns `None`, search moves to parent widget

> - If no target widget is found, then the target object is `None`

2. Call to <old_target>.dnd_leave(source, event)

3. Call to <new_target>.dnd_enter(source, event)

4. Call to <target>.dnd_commit(source, event) to notify of drop

5. Call to <source>.dnd_end(target, event) to signal end of drag-and-drop

class tkinter.dnd.DndHandler(source, event)

  The DndHandler class handles drag-and-drop events tracking Motion and ButtonRelease events on the root of the event widget.

  cancel(event=None)

    Cancel the drag-and-drop process.

  finish(event, commit=0)

    Execute end of drag-and-drop functions.

  on_motion(event)

    Inspect area below mouse for target objects while a drag is performed.

  on_release(event)

    Signal end of drag when the release pattern is triggered.

tkinter.dnd.dnd_start(source, event)

  Factory function for the drag-and-drop process. Return the `DndHandler` instance managing the drag, or `None` if a drag could not be started.

See also

Bindings and events