Binding just converts a variable into a property by wrapping in function get/set. The best practice to dispatch an event from the setter and declare the event name in the [Bindable] metadata.
I thought there was a warning for binding to private, but maybe we got around it somehow. Binding is one way, but if the dg is bound to employees, the underlying array that got passed into the ArrayCollection should get modified when you drop into the dg. -Alex ________________________________ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Geoffrey Sent: Monday, May 21, 2007 2:41 PM To: [email protected] Subject: [flexcoders] Re: Does Drag & Drop Only Update the DataProvider? Why is binding to private variables not recommended? Should I bind to the employees pseudo property? I figured out why it wasn't working. Binding is one way. I'm binging the DataGrids dataProvider to the ArrayCollection, so only changes to the ArrayCollection would effect the dataProvider. It doesn't work the other way around (changes to the DataProvider updating the ArrayCollection). Somehow I seemed to have forgotten that fact. --- In [email protected] <mailto:flexcoders%40yahoogroups.com> , "Alex Harui" <[EMAIL PROTECTED]> wrote: > > collectionChange is dispatched from the collection and not the DataGrid. > > > > Binding to private variables is not recommended, but not the problem > either. > > > > Can you fit an entire example in two screens of text? If so, post it. > > > > ________________________________ > > From: [email protected] <mailto:flexcoders%40yahoogroups.com> [mailto:[email protected] <mailto:flexcoders%40yahoogroups.com> ] On > Behalf Of Geoffrey > Sent: Monday, May 21, 2007 9:56 AM > To: [email protected] <mailto:flexcoders%40yahoogroups.com> > Subject: [flexcoders] Re: Does Drag & Drop Only Update the DataProvider? > > > > collectionChange doesn't appear to be a valid DataGrid event, but I > tried dataChanged, added, add, valueCommit, and updateComplete. None > of these did what I wanted, and actually, I have verified that the > __employees ArrayCollection does not update after a D&D event. > > Looking through everything in debug mode, I'm seeing that the > dataProvider of the DataGrid is updated after D&D, but not the bound > variable __employees. > I wonder if it's how I declared the variable? I did it like so: > <code> > [Bindable] > private var __employees:ArrayCollection; > > public function get employees():ArrayCollection { > return __employees; > } > > public function set employees( employees:ArrayCollection ):void { > if (employees != null) { > __employees = employees; > } > } > </code> > > Maybe I should just make it public? Nope, that didn't work. > > I'm also wondering if the "event.preventDefault();" is messing > something up. Nope, that just prevents the the base class ListBase > from doing it's D&D handling. Since this doesn't check for > duplicates, I don't want to use it. > > I'm not sure what to do.... > > --- In [email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:flexcoders%40yahoogroups.com> > , "Alex Harui" <aharui@> wrote: > > > > Mx:DataGrid's change event is for when selection changes, not when the > > collection changes. Could that be the issue? collectionChange may be > > what you want. > > > > > > > > ________________________________ > > > > From: [email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:flexcoders%40yahoogroups.com> > [mailto:[email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:flexcoders%40yahoogroups.com> > ] On > > Behalf Of Geoffrey > > Sent: Friday, May 18, 2007 10:12 AM > > To: [email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:flexcoders%40yahoogroups.com> > > Subject: [flexcoders] Re: Does Drag & Drop Only Update the > DataProvider? > > > > > > > > I don't have the code in front of me right now, but to be more > precise, > > dgEmployees is not > > broadcasting a change event upon a D&D action. I want dgEmployees to > > broadcast an > > event every time there is a change to the DataGrid. The dgEmployees > > DataGrid has a > > change event method defined, somthing like: > > > > <code> > > <mx:DataGrid id="dgEmployees" > > dataProvider="{__employees}" > > change="broadcastEvent(event)" > > ...> > > </code> > > > > The broadcastEvent() method constructs a custom event containing the > > number of > > elements in the DataGrid, and then dispatches it to be used elsewhere. > > > > Now, as I type this, I see that I might have keyed off the wrong > event, > > "change". Not sure if > > that is broadcast upon a change in the dataProvider, BUT I had been > > working on this code > > previously (converting to Flex 2.0), and I believe that I saw this > same > > issue. > > > > I noticed that when I used the debugger to step throught the > > doDragDrop() method, I was > > seeing that only the dataProvider was being updated, and not the > > ArrayCollection. I can't > > verify this until Monday (5/21), but I'm almost 100% sure this is what > I > > saw. > > > > --- In [email protected] <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > > , "Alex Harui" <aharui@> wrote: > > > > > > How do you know it didn't update __employees? > > > > > > > > > > > > Can you post a mini-example in a couple of screenfuls of text? > > > > > > > > > > > > ________________________________ > > > > > > From: [email protected] <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > > [mailto:[email protected] <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > > ] On > > > Behalf Of Geoffrey > > > Sent: Thursday, May 17, 2007 6:11 PM > > > To: [email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > > > Subject: [flexcoders] Does Drag & Drop Only Update the DataProvider? > > > > > > > > > > > > I have a DataGrid that has a dataProvider bound to an > ArrayCollection. > > > > > > <code> > > > <mx:DataGrid id="dgEmployees" > > > dataProvider="{__employees}" > > > ...> > > > </code> > > > > > > I also have another DataGrid (dgAllEmployees) that is within a > popup, > > > which I use as a source for Drag & Drop operations to populate the > > > dgEmployee dataGrid. > > > > > > What I've noticed is that when I drag & drop employees from the "all > > > employees" DataGrid to the "employees" DataGrid, it seems to only > > > update the dataProvider of dgEmployees, and not the ArrayCollection > > > __employees. Why is this? > > > > > > Below is a snip of my drag & drop code where it actually copies the > > > data. This is a generic method that is used all over the > application. > > > <code> > > > public static function doDragDrop( event:DragEvent ):void > > > { > > > // Prevent the default event from happening. > > > event.preventDefault(); > > > > > > // Get drop target > > > var dropTarget:DataGrid = DataGrid(event.currentTarget); > > > > > > // Get the dragged items from the drag initiator. > > > var dropItems:Array = event.dragSource.dataForFormat("items") as > > Array; > > > > > > // Add each item to the drop target. > > > for (var i:uint = 0; i < dropItems.length; i++) > > > { > > > var dest:IList = IList(dropTarget.dataProvider); > > > if (!contains(dest, dropItems[i])) > > > { > > > dest.addItem(dropItems[i]); > > > } > > > } > > > } > > > </code> > > > > > > I think that I had event.preventDefault(); in there because it was > > > putting 2 of each dropped item in the dgEmployee DataGrid. Might > this > > > be messing something up? > > > > > > Also, contains() is a custom method to compare the source items to > > > what's in the target's list to prevent duplicates. Is there a better > > > way to do this? > > > > > > Thanks in advance. > > > GT > > > > > >
