Question

I’m using Dojo dnd version 1.7.2 and it’s generally working really well. I’m happy.

My app maintains many arrays of items, and as the user drags and drops items around, I need to ensure that my arrays are updated to reflect the contents the user is seeing.

In order to accomplish this, I think I need to run some code around the time of Source.onDndDrop

If I use dojo.connect to set up a handler on my Source for onDndDrop or onDrop, my code seems to get called too late. That is, the source that’s passed to the handler doesn’t actually have the item in it any more.

This is a problem because I want to call source.getItem(nodes[0].id) to get at the actual data that’s being dragged around so I can find it in my arrays and update those arrays to reflect the change the user is making.

Perhaps I’m going about this wrong; and there’s a better way?

Answer 1

Ok, I found a good way to do this. A hint was found in this answer to a different question:
https://stackoverflow.com/a/1635554/573110

My successful sequence of calls is basically:

var source = new dojo.dnd.Source( element, creationParams );
var dropHandler = function(source,nodes,copy){
  var o = source.getItem(nodes[0].id); // 0 is cool here because singular:true.
  // party on o.data ...
  this.oldDrop(source,nodes,copy);
}
source.oldDrop = source.onDrop;
source.onDrop = dropHandler;

This ensures that the new implementation of onDrop (dropHandler) is called right before the previously installed one.