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:[EMAIL PROTECTED] On Behalf Of ben.clinkinbeard Sent: Friday, November 09, 2007 6:03 PM To: [email protected] 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> , "Alex Harui" <[EMAIL PROTECTED]> 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:[email protected] <mailto:flexcoders%40yahoogroups.com> ] On > Behalf Of ben.clinkinbeard > Sent: Friday, November 09, 2007 12:29 PM > To: [email protected] <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> > , "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> , "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> , "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 > > > > > > > > > >
