Problems when deselecting checkboxes inside bound NSTableview's columns

问题

I am using this project, created by aneesh171 that shows the creation of checkboxes inside NSTableView and how to bind them. I am new to OSX development and trying to understand how it works.

The project is basically checkboxes inside a NSTableView's column that is bound to an array controller.

For some reason, when I deselect one of those checkboxes, the following messages appear on the console window:

2014-04-03 04:22:55.579 MyApp[5735:303] Error setting value for key path objectValue.selected of object <NSAutounbinder: 0x600000258120 - a nonretaining proxy for <NSTableCellView: 0x60000019f890>> (from bound object <NSButton: 0x60000015efb0>): [<__NSDictionaryI 0x61000006f540> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key selected.
2014-04-03 04:22:55.581 MyApp[5735:303] (
    0   CoreFoundation                      0x00007fff87b3a25c __exceptionPreprocess + 172
    1   libobjc.A.dylib                     0x00007fff8a3f6e75 objc_exception_throw + 43
    2   CoreFoundation                      0x00007fff87b3a038 +[NSException raise:format:arguments:] + 104
    3   AppKit                              0x00007fff927936c5 -[NSBinder _setValue:forKeyPath:ofObject:mode:validateImmediately:raisesForNotApplicableKeys:error:] + 837
    4   AppKit                              0x00007fff92793327 -[NSBinder setValue:forBinding:error:] + 245
    5   AppKit                              0x00007fff92c8b4ee -[NSValueBinder _applyObjectValue:forBinding:canRecoverFromErrors:handleErrors:typeOfAlert:discardEditingCallback:otherCallback:callbackContextInfo:didRunAlert:] + 194
    6   AppKit                              0x00007fff92c8b871 -[NSValueBinder applyDisplayedValueHandleErrors:typeOfAlert:canRecoverFromErrors:discardEditingCallback:otherCallback:callbackContextInfo:didRunAlert:error:] + 621
    7   AppKit                              0x00007fff927c5107 -[NSValueBinder performAction:] + 288
    8   AppKit                              0x00007fff927c4fc5 -[_NSBindingAdaptor _objectDidTriggerAction:bindingAdaptor:] + 133
    9   AppKit                              0x00007fff927531a0 -[NSControl sendAction:to:] + 56
    10  AppKit                              0x00007fff9279fced -[NSCell _sendActionFrom:] + 128
    11  AppKit                              0x00007fff927b96c5 -[NSCell trackMouse:inRect:ofView:untilMouseUp:] + 2316
    12  AppKit                              0x00007fff927b8a97 -[NSButtonCell trackMouse:inRect:ofView:untilMouseUp:] + 487
    13  AppKit                              0x00007fff927b81ad -[NSControl mouseDown:] + 706
    14  AppKit                              0x00007fff92739b48 -[NSWindow sendEvent:] + 11296
    15  AppKit                              0x00007fff926d86e4 -[NSApplication sendEvent:] + 2021
    16  AppKit                              0x00007fff92528b89 -[NSApplication run] + 646
    17  AppKit                              0x00007fff92513913 NSApplicationMain + 940
    18  MyApp                               0x0000000100049132 main + 34
    19  libdyld.dylib                       0x00007fff85ffe5fd start + 1

When the checkbox is selected this message does not show on the console.

Can you guys tell me what is wrong?

回答1:

I updated the git version of the project.

Whenever you bind a control through value binding, then it calls its getter method to load the values. whereas when you tries to modify these values, it will try to call the setter method of the property. In the project the dictionaries were hardcoded therefore there were no setter method and that is the reason why you got the "Error setting value for key path objectValue.selected".

Check the new version where the FruitModel has been created which resolves the setter issue.

Let me know if you face any problems.

来源：https://stackoverflow.com/questions/22827414/problems-when-deselecting-checkboxes-inside-bound-nstableviews-columns