Newbie Help Needed: Data Binding

Question

Okay, lemme see if I can possibly explain this issue clearly
enough... (The whole explanation of the object graph may very well
be superfluous, so you can probably skip to the bottom.)
I have a whole object graph that I've downloaded from my
server to my Flex client. Here's the general gist of object
relationships (and I have to lay it out this way because there's
not really any way to sketch on a whiteboard the object graph):
Object A is a parent of object B, and there is a one-to-many
relationship between the two. That is, there is one A to many B's.
There is a one-to-one relationship between Object B and
Object C.
There is a many-to-one relationship between Object C and
Object D. That is, there are many C's to one D.
There is a many-to-one relationship between Object D and
Object E. That is, there are many D's to one E.
There is a many-to-one relationship between Object E and
Object F. That is, there are many E's to one F.
Now, because I am only given information from the user as far
as which object A is the chosen object (that is, I'm not told right
off the bat which B's, C's, D's, E's, and F's to pull from the
server), I have a series of events being fired and listened to, so
the sequence of steps pretty much goes like this:
User chooses a particular object A.
I pull A from the server.
I pull all of A's children (the B objects).
I look at the keys stored in the B's and pull the
corresponding C's.
I look at the keys stored in the C's and pull their parents,
the D's.
I look at the keys stored in the D's and pull their parents,
the E's.
I look at the keys stored in the E's and pull their parents,
the F's.
Now, here's where I'm having an issue:
The B objects store a Date object called startTime. The D
objects store an integer called runTimeMillis (the runtime of the
video, in milliseconds). I need to somehow present endTime, which
is simply the sum of startTime + runTimeMillis. But I have to do it
in a data binding because the D objects are downloaded later than
the B objects. But I've tried so many different ways of coding it,
and nothing seems to work. Here's where I'm at:
<mx:DateFormatter id="hmmssaFormatter"
formatString="L:NN:SSA"/>
<mx:Label text="{hmmssaFormatter.format(B.startTime +
B.C.D.runTimeMillis)}" fontWeight="bold"/>
The only thing I get in my client is a blank label. What am I
doing wrong? The following seems to work just fine in displaying
the start time of the video:
<mx:Label text="{hmmssaFormatter.format(B.startTime)}"
fontWeight="bold"/>
But adding a number of milliseconds doesn't seem to work at
all. Can anyone shed some light on the matter? Thanks!

Answer 1

"Noreaster76" <[email protected]> wrote in
message
news:[email protected]...
> Okay, lemme see if I can possibly explain this issue
clearly enough...
> (The
> whole explanation of the object graph may very well be
superfluous, so you
> can
> probably skip to the bottom.)
>
> I have a whole object graph that I've downloaded from my
server to my Flex
> client. Here's the general gist of object relationships
(and I have to
> lay it
> out this way because there's not really any way to
sketch on a whiteboard
> the
> object graph):
>
> Object A is a parent of object B, and there is a
one-to-many relationship
> between the two. That is, there is one A to many B's.
> There is a one-to-one relationship between Object B and
Object C.
> There is a many-to-one relationship between Object C and
Object D. That
> is,
> there are many C's to one D.
> There is a many-to-one relationship between Object D and
Object E. That
> is,
> there are many D's to one E.
> There is a many-to-one relationship between Object E and
Object F. That
> is,
> there are many E's to one F.
>
> Now, because I am only given information from the user
as far as which
> object
> A is the chosen object (that is, I'm not told right off
the bat which B's,
> C's,
> D's, E's, and F's to pull from the server), I have a
series of events
> being
> fired and listened to, so the sequence of steps pretty
much goes like
> this:
>
> User chooses a particular object A.
> I pull A from the server.
> I pull all of A's children (the B objects).
> I look at the keys stored in the B's and pull the
corresponding C's.
> I look at the keys stored in the C's and pull their
parents, the D's.
> I look at the keys stored in the D's and pull their
parents, the E's.
> I look at the keys stored in the E's and pull their
parents, the F's.
>
> Now, here's where I'm having an issue:
> The B objects store a Date object called startTime. The
D objects store an
> integer called runTimeMillis (the runtime of the video,
in milliseconds).
> I
> need to somehow present endTime, which is simply the sum
of startTime +
> runTimeMillis. But I have to do it in a data binding
because the D
> objects are
> downloaded later than the B objects. But I've tried so
many different
> ways of
> coding it, and nothing seems to work. Here's where I'm
at:
>
> <mx:DateFormatter id="hmmssaFormatter"
formatString="L:NN:SSA"/>
> ...
> <mx:Label text="{hmmssaFormatter.format(B.startTime +
> B.C.D.runTimeMillis)}"
> fontWeight="bold"/>
>
>
> The only thing I get in my client is a blank label. What
am I doing
> wrong?
> The following seems to work just fine in displaying the
start time of the
> video:
>
> <mx:Label
text="{hmmssaFormatter.format(B.startTime)}" fontWeight="bold"/>
>
> But adding a number of milliseconds doesn't seem to work
at all. Can
> anyone
> shed some light on the matter? Thanks!
I still think there's something unexpected going on with your
data. In the
function where you set C and D, can you put a breakpoint and
inspect the
variables? You could also probably put a break point in the
formatter and
see shat has been passed in to it.
HTH;
Amy