Re: NS(Array)Controller and To-Many Relationships (how to add objectsfrom one to another)
Re: NS(Array)Controller and To-Many Relationships (how to add objectsfrom one to another)
- Subject: Re: NS(Array)Controller and To-Many Relationships (how to add objectsfrom one to another)
- From: アンドレ（Andre） <email@hidden>
- Date: Sun, 6 Feb 2005 18:04:45 -0800
Note that arrangedObjects and selectedObjects are arrays (also for a
single selection), not the selected object itself. You should use
Controller Key: selection
Model Key Path: columns
Just did it, and it all works now.
But I don't understand what is the difference between
selection and selectedObjects/arrangedObjects?
I think this is maybe why some people want a bindings book (maybe
better a coredata book)
because while there is a lot of documentation, its a little assuming we
already know 'certain' things....
If someone could explain everything in a more detailed and bottom-up
way it might be nice....
In any case, thanks a lot for your help!
I appreciate it.
On 平成 17/02/06, at 1:42, Christiaan Hofman wrote:
On Feb 6, 2005, at 10:49, アンドレ（Andre） wrote:
The first ArrayController controls the first array, so the 'add'
method adds an instance of object1 to the array, while it allows you
to select a particular object1 (the selection). Now you want to add
an object2 to the array in selected object1. Do I understand you
correctly?
Yes this is exactly it.
If so, what you need to do is to bind the content of the second
NSArrayController to the selection of the first NSArrayController,
with the model keypath given by the key for the array which contains
the object2-s (which is columns, if I understand your example).
I actually tried something similar, I bound the content of the
controller2 to the selection.columns of the
first one. but I still had problems because the console output said
something about the returned object
not being compliant...
Heres my binding for the second controller to the first:
<Picture 2.png>I tried selectedObjects but got errors too....
Note that arrangedObjects and selectedObjects are arrays (also for a
single selection), not the selected object itself. You should use
Controller Key: selection
Model Key Path: columns
For this part, it should work, at least it does for me. If there is
still an error, I guess it is at another stage.
You should implement KVC array accessors in object1, like
insertObject:inColumnsAtIndex:. Then -add: of the second
NSArrayController adds an object2 to the columns array of the
selected object1.
I see what your saying. I'll go ahead and implement that and see
what happens... though I'm a little
lost as to WHAT exactly I should do in this method... I've read just
about everything, but the stuff
about bindings (especially through IB) makes everything seem almost
all automatic... especially the
stuff thats coming...
I follow your suggestion!
Though shouldn't the NSArrayController know how to handle all those
things if I had my object
and one of its variables is an NSArray?
I think so. However it is always best to implement the KVC compliant
array accessors, which in your case probably just echo anything to the
columns array. So do things like
- (id)objectInColumnsAtIndex:(unsigned int)index {
[columns objectAtIndex:index];
}
See the documentation on which KVC methods to implement (they are
basically the same as the array accessors with "InColumns" added, or
whatever the name is).
Also, make sure that the Object Class Name of the arraycontrollers is
set to the class in your array (but this is only relevant for adding
though).
Christiaan
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