canceling drag between connected lists drops item

[brendanblackwood]

I'm trying to cancel dragging an item from one list to another if certain conditions are met (in the example, max list size).

http://codepen.io/anon/pen/toDej

Try to have more than 10 things in one of the lists. Visually, there are no problems, but if you log out the results, you see items are getting removed from one list and not put back. It could be that I'm approaching this wrong, but I'm running out of ideas.

Oh, and I am using the angular1.2 branch.

[thgreasi]

You should use the model to count the length of the list, not the DOM elements.

[brendanblackwood]

Fair enough. The same problem will persist, however. Canceling the sort will replace the item in the proper place in the DOM, but it will not replace the model. That just gets lost.

New codepen with model checking: http://codepen.io/anon/pen/fAvCJ

[thgreasi]

Here is the order that the events fire on connected lists:

strart      0
activate    1
activate    0
update      0
remove      0
receive     1
update      1
stop        0

As far as I know the best time to call cancel() is inside the first update callback. Receive and update on the receiving list is too late, since the first model has already been altered.
Here is a pen utilizing the changes of #108.

Feel free to reopen if necessary.

[brendanblackwood]

Works great. Thanks!

[jegesh]

How would I go about cancelling a drag between lists, but allowing ordering within a list, only for certain elements (validation)? When I try to cancel when remove fires from the original list, the element stays put, but becomes unorderable thereafter. Debugging it, I see that ui.item.sortable.model is undefined.

[thgreasi]

You can place your logic in the update callback and use the properties of
the ui.item.sortable object (ui is the second argument of the callback).
Take a look at the examples and documentation in README.md and API.md .

Thodoris Greasidis
Computer, Networking &
Communications Engineer

[jegesh]

I tried doing that, but I need to know if it's just a sort within the list, or moving to a second list. There is no indication of this until either the second update is hit, or remove of the first list gets hit, in either too late to cancel the action, because the update call of the original list happens before that. I'm looking for a way to either determine already in the first update if it's a move or an ordering, or alternatively a way to 'manually' call the update callback from within the remove callback of the same list.

[thgreasi]

As noted in API.md, you can use the droptarget and droptargetModel properties and possibly compare them with source and sourceModel properties, to check whether it's a connected-list sorting.