I'll try to remember to investigate some of the nooks and crannies of 'function-casting' in AS someday. I just know that I've seen some differences between what worked in C++ and Java and what works in AS, especially around primitive types.
________________________________ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of ben.clinkinbeard Sent: Saturday, November 10, 2007 7:00 AM To: [email protected] Subject: [flexcoders] Re: Casting in flex So then is the technical/traditional definition of casting different from the behavior you describe? (The creation of a new Object pointer) Just trying to fully understand things here. Thanks, Ben --- In [email protected] <mailto:flexcoders%40yahoogroups.com> , "Alex Harui" <[EMAIL PROTECTED]> wrote: > > It is the same object in almost all cases except for primitive types > > > > ________________________________ > > From: [email protected] <mailto:flexcoders%40yahoogroups.com> [mailto:[email protected] <mailto:flexcoders%40yahoogroups.com> ] On > Behalf Of Alex Birch > Sent: Friday, November 09, 2007 7:02 PM > To: [email protected] <mailto:flexcoders%40yahoogroups.com> > Subject: Re: [flexcoders] Re: Casting in flex > > > > Is it a new object? Or just an object pointer of the specified type? > I.e., are there now 2 memory locations or just one memory location? > > > > On Nov 9, 2007 6:50 PM, Alex Harui < [EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]> > wrote: > > I think of it as casting, but I believe it really is a function call > that returns an object of that type > > > > ________________________________ > > From: [email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:[email protected] <mailto:flexcoders%40yahoogroups.com> > > [mailto:[email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:[email protected] <mailto:flexcoders%40yahoogroups.com> > ] > On Behalf Of ben.clinkinbeard > Sent: Friday, November 09, 2007 6:03 PM > To: [email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:[email protected] <mailto:flexcoders%40yahoogroups.com> > > Subject: [flexcoders] Re: Casting in flex > > > > Good point Alex, I guess conversion does occur when dealing with > primitives. As for there being no casting in AS, how would you > describe what happens with complex types? Like dog = Dog(animalArg) > from below. > > Ben > > --- In [email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:flexcoders%40yahoogroups.com> > , "Alex Harui" <aharui@> wrote: > > > > Excellent description of casting, but IMHO, there is no casting in AS. > > Using a function to 'cast' like Number("5") actually does do a > > conversion in some cases as does 5.5 as int > > > > > > > > To the original question, your data should be converted to Position > > objects automatically if you got set up correctly. I'm not an expert > in > > that area, but RegisterClassAlias should be part of the solution. > > > > > > > > ________________________________ > > > > 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 ben.clinkinbeard > > Sent: Friday, November 09, 2007 12:29 PM > > To: [email protected] <mailto:flexcoders%40yahoogroups.com> <mailto:flexcoders%40yahoogroups.com> > > Subject: [flexcoders] Re: Casting in flex > > > > > > > > Yes, casting does not actually convert anything from one type to > > another. Casting simply allows you to refer to an object by a type > > that it already is, but that its not specifically defined as. > > > > I know that sounds confusing, so let me explain a bit. You could have > > a method that accepted an argument of type Animal, because you want to > > be able to send any subtype of Animal to the function, such as Dog, > > Cat, Fish, etc. Inside that function, if you wanted to call methods > > that were specific to the subclass passed in, you could do a check and > > then a cast. So maybe the method body would look like this: > > > > animalArg.feed(); > > > > // specific actions > > if(animalArg is Dog){ > > var dog:Dog = Dog(animalArg); > > dog.walk(); > > } > > else if(animalArg is Fish){ > > var fish:Fish = Fish(animalArg); > > fish.flush(); > > } > > > > Also, I don't think the as operator is exactly the same as a cast but > > its very similar and I don't feel like looking up the difference right > > now. My suggestion would be to convert your objects when the result is > > returned and then not have to worry about casting them later. You can > > just make the Position class constructor accept an Object and pull the > > properties off of it. > > > > HTH, > > Ben > > > > --- In [email protected] <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com > <mailto:flexcoders%40yahoogroups.com> > > > , "luciddream54321" <asoltys@> wrote: > > > > > > Hi, > > > > > > I'm working with Arash on this project. Thanks for the suggestions > > > but even using these alternate methods for geting the selectedItem > the > > > cast to a Position object still fails. > > > > > > Our dataProvider is an ArrayCollection that is populated by a > > > ColdFusion query returned from a RemoteObject call. The query rows > > > are from our positions table but flex is storing the rows as generic > > > 'Objects' within the ArrayCollection. Here is the line we use in our > > > RemoteObject result handler: > > > > > > positions = event.result as ArrayCollection; > > > > > > Using the debugger we've been able to verify that the Objects in the > > > ArrayCollection do have the same public properties as our Position > > > value object. > > > > > > So is it necessary to convert the query rows into Position objects > > > immediately when they come back from ColdFusion rather than casting > > > them after we get them out of the ArrayCollection? How would this be > > > done exactly? > > > > > > Adam > > > > > > --- In [email protected] <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > > <mailto:flexcoders%40yahoogroups.com > <mailto:flexcoders%40yahoogroups.com> > , "ben.clinkinbeard" > > > <ben.clinkinbeard@> wrote: > > > > > > > > I assume your dataProvider is a collection of Position objects? Is > > it > > > > an ArrayCollection? > > > > > > > > Try changing this line > > > > > > > > selectedItem = event.currentTarget.dataProvider[selectedRow]; > > > > > > > > to this > > > > > > > > selectedItem = > > event.currentTarget.dataProvider.getItemAt(selectedRow); > > > > > > > > HTH, > > > > Ben > > > > > > > > > > > > --- In [email protected] <mailto:flexcoders%40yahoogroups.com> > <mailto:flexcoders%40yahoogroups.com> > > <mailto:flexcoders%40yahoogroups.com > <mailto:flexcoders%40yahoogroups.com> > , "arashafrooze" > <arash.afrooze@> > > > > wrote: > > > > > > > > > > Hi, > > > > > I'm a flex newbie, so please bear with me ... > > > > > I have an advanced datagrid with a change property that calls a > > > > > function passing it the event. > > > > > inside the function i retrieve the selected row and cast it as > an > > > > > object. then i try to cast this object as, what i call a > Position > > > > > object. Even though both objects are identical in properties, My > > > > > postion object does not get populated and is assigned NULL. > > > > > I'm pasting the code to my function. > > > > > Any help is greatly appreciated. > > > > > > > > > > > > > > > public function updateSelectedPosition(event:Event):void > > > > > { > > > > > var position:Position = new Position(); > > > > > var selectedItem:Object; > > > > > var selectedRow:uint = event.target.selectedCells[0].rowIndex; > > > > > selectedItem = event.currentTarget.dataProvider[selectedRow]; > > > > > position = selectedItem as Position; > > > > > } > > > > > > > > > > Thank you all so very much in advance :D > > > > > > > > > > > > > > > > > > > -- > ~~ > http://www.lifesabirch.org <http://www.lifesabirch.org> <http://www.lifesabirch.org <http://www.lifesabirch.org> > >
