feat(drag-drop): prevent a item be removed when it into another container

Feature Description

CDK(V9) provide [cdkDropListEnterPredicate] to prevent a item into another container, provide (cdkDropListDropped) to determine how to do when user drop the item.

I found when user drag the item into another container but not to release, the item is removed in origin container. When I release it, I didn’t add (cdkDropListDropped), so the item is recovered. But what I want is the item can into another container but not to be removed in any time.

In summary, can you provide (cdkDragLeaved) to determine how to deal with the item when the item into another container?

Use Case

Just imaging you are ordering foods from menu in the restaurant. You need to drag the food into your shopping cart. But the item of the menu should’t be removed.

[devversion]

Hi @Mr-Eve. great issue! thanks. I think what you are trying to achieve should be partially possible already by just not using the move or transfer utilities the drag-drop provides, but rather by “copying” the element. For example:

    if (event.previousContainer.id === 'menu') {
      event.container.data.splice(event.currentIndex, 0,
        event.previousContainer.data[event.previousIndex]);
    }

The only problem I see here is that the drag placeholder from the menu list is temporarily removed when the item is being dragged over the Shopping cart drop list. cc. @crisbeto

[andreElrico]

@Mr-Eve is what you want a copy feature? something like here?

https://stackblitz.com/edit/angular-krmecd (from #13906)

Check https://github.com/angular/components/issues/13906

• If thats what you want, close this one and put a thumbs up on issue #13906
• There are also some workarounds provided.