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Re: Add keys programatically to NSArrayController? [solved]

Ok after some more digging I think I found a solution. It is not adding keys to the array controller.

Instead:

Keep the collection of attributes you want to represent in new columns in an NSMutableDictionary. Call the collection - say - someObjects.

In IB manually add the key "someObjects" to the NSArrayController in the nib file for the table

When adding a column to the table during program execution, add a dictionary entry with key @"new1" to the someObjects ivar of each object in the array. This will be the contents of the table cell for that object in the new column.

Then (this is in code now) bind the first new column using

[newColumn bind:@"value" toObject:tableController withKeyPath:@"arrangedObjects.someObjects.new1" options:nil];

The default implementation of valueForKeyPath will then get the dictionary someObjects and return the result of sending it valueForKey:@"new1"

This is pretty cool - I had not used the someObject.someKey functionality before. I think bindings are awesome - in the end my new columns scheme took about ten lines of code, but hope the retain cycle thing will be fixed soon... (yes I've filed a bug).

Rick

On Jul 31, 2004, at 7:23 AM, Rick Hoge wrote:

Is there any way, using Objective-C calls, to add new keys to an existing instance of NSArrayController?

I have an NSTableView in which I'd like to be able to allow the user to add an arbitrary number of columns whose value would be bound to keys in a custom class. My plan was to generate new keys automatically (e.g. @"key1",@" key2", ...) and have my custom class provide appropriate values by parsing these keys in valueForKey: . The arbitrary number of columns would correspond to an aribitrary number of object attributes in the custom class

For this scheme to work, I need to be able to add @"key1" to the NSArrayController I'm using to serve my list of objects to the table when a column is added. Such functionality does not seem to be included in the docs for NSObjectController and NSArrayController - anyone know if it is possible?

Obviously my 'arbitrary number of object attributes' would be best modeled as an NSArray instance variable in the custom class. I don' know how you would associate specific elements in the array with the appropriate columns through bindings though. I'm already using bindings in this table and, as this has been working well for me (up to this), would like to stick to this approach if possible.

Thanks for any suggestions,

Rick
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References: 
 >Add keys programatically to NSArrayController? (From: Rick Hoge <email@hidden>)



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