association between views and model objects

Question

What is the best approach for managing the association between a UIView (like a UIButton) and the model object to which they relate?

Example (made-up): Lets assume that I have a StoreViewController with this code:

- (void)viewDidLoad
{
    for(int i = 0; i < [self.storeItems count]; ++i) {
        StoreItem* item = [self.storeItems objectAtIndex:i];
        UIButton* button = [[UIButton alloc] initWithFrame:[...]];
        [button addTarget:self
                   action:@selector(itemButtonPressed:)
         forControlEvents:UIControlEventTouchDown];

        [button setTitle:item.text forState:UIControlStateNormal];

        // THIS PART!
        button.tag = i; // assuming approach 1 on the following paragraph

        [self.someView addSubView:button];
    }
    [super viewDidLoad];
}

In my event code how do I relate back to my item?

- (void)itemButtonPressed:(UIButton*)button;
{
    // THIS PART!
    StoreItem* item = [self.storeItems objectAtIndex:button.tag; // assuming approach 1

    [self addToCart:item];
}

I am already aware of some approaches:

1. Assuming that the model is in a list (like an NSArray) set the tag attribute of the button to the same value as the object index in the list. (note: this seems to be the best option so far, but it will not work if your data is not in a list)
2. Have a NSDictionary that associates buttons to store items. (very flexible but not very nice to maintain since you need to add a NSDictionary to your StoreViewController for every association)
3. Custom views may have a userInfo dictionary. (this works well for ASIHTTPRequest, what are the downsides of using this in a view?)
4. ???

Which approach do you think is the best?

What if this is a custom view and you can add fields at will? Is the userInfo approach recommended?

related:

• Detecting which UIButton was pressed in a UITableView