nsIClipboardDragDropHooks

IID:e03e6c5e-0d84-4c0b-8739-e6b8d51922de
Inherits From:nsISupports

Interfaces for overriding the built-in drag, drop, copy, and paste implementations in the content area and editors. Use this to do things such as prevent a drag from starting, adding or removing data and flavors, or preventing the drop.

Embedders who want to have these hooks made available should implement nsIClipboardDragDropHooks and use the command manager to send the appropriate commands with these parameters/settings: command: cmd_clipboardDragDropHook

Params value type possible values "addhook" isupports nsIClipboardDragDropHooks as nsISupports "removehook" isupports nsIClipboardDragDropHooks as nsISupports

Notes: Overrides/hooks need to be added to each window (as appropriate). Adding them to the first window does not enable them for every window. If more than one implementation is set for a window, the hooks will be called in the order they are added. Adding the same hook to the same window will not add a second call. Each hook can only be called once per user action/api. Not all hooks are guaranteed to be called. If there are multiple hooks set for a window, any of them has an opportunity to cancel the action so no further processing will occur. If any errors occur (without setting the boolean result) the default action will occur. AllowDrop will be called MANY times during drag so ensure that it is efficient.


Methods

PRBool allowDrop ( nsIDOMEvent event , nsIDragSession session ) PRBool allowStartDrag ( nsIDOMEvent event ) PRBool onCopyOrDrag ( nsIDOMEvent event , nsITransferable trans ) PRBool onPasteOrDrop ( nsIDOMEvent event , nsITransferable trans )

PRBool allowDrop ( nsIDOMEvent event , nsIDragSession session )

Tells gecko whether a drop is allowed on this content area

Arguments:
event: DOM event (drag over)
session: the drag session from which client can get the flavors present or the actual data
Returns:
FALSE indicates to OS drop is not allowed. On win32, this will change the cursor to "reject".

PRBool allowStartDrag ( nsIDOMEvent event )

Prevents the drag from starting

Arguments:
event: DOM event (drag gesture)
Returns:
FALSE drag is cancelled, does not go to OS

PRBool onCopyOrDrag ( nsIDOMEvent event , nsITransferable trans )

Alter the flavors or data presented to the OS Used for drag and copy actions Because this can be called many times, it is highly recommended that the implementation be very efficient so user feedback is not negatively impacted.

Arguments:
event: DOM event (drag drop); null if triggered by copy.
trans: the transferable holding the list of flavors and the data for each flavor
Returns:
FALSE copy/drag is cancelled, does not go to OS

PRBool onPasteOrDrop ( nsIDOMEvent event , nsITransferable trans )

Provide an alternative action to the built-in behavior when something is dropped on the browser or in an editor

Arguments:
event: DOM event (drag drop); null if triggered by paste.
trans: the transferable holding the list of flavors and the data for each flavor
Returns:
FALSE action was not overridden, do built-in behavior

References

This interface is passed as an argument to the following methods:

nsIClipboardDragDropHookList.addClipboardDragDropHooks, nsIClipboardDragDropHookList.removeClipboardDragDropHooks

Reference documentation is generated from Mozilla's source.

Add a note User Contributed Notes
No comments available

Copyright © 1999 - 2005 XULPlanet.com