Core Data calculation result at startup

Thanks for the help.

I have a doc based Core Data app consisting of a table with two columns. The column cells are populated with US Currency dollar values. I have two labels at the bottom of each column with Number formatters. Each label displays the sum of it's respective column. I'm doing this with bindings:

• Bound to the arrayControlle开发者_如何学编程r
• Controller Key - arrangedObjects
• modelKey - @sum.regAmount, @sum.regAmount1

The label attribute Types are int 16 in the data model.

Anyway, these calculations work fine, and the resulting values are displayed at startup.

What I need to do is also display the difference between the two resulting sums at startup in a third label. For some reason I can't pick up the sum values to preform the calculation.

This action works using a sender:

(runningBalance.intValue = (theDeposits.intValue - theAmounts.intValue)); 

How can I automatically display the calculated difference of the two sums at startup without manually executing the action?

Thanks again.

Paul

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You don't need an action, you need a model key you can bind to just as you do with the sums. Then you bind that to the label's display(?) property and it should be called automatically.