在这里我有不同的单元格.每个单元格都有一个模型.使用KVO和NotificationCenter,单元格会收听模型以进行更改.当我离开ViewController我得到这个错误：

An instance 0x109564200 of class Model was deallocated while key value observers were still registered with it. 
Observation info was leaked,and may even become mistakenly attached to some other object. 
Set a breakpoint on NSKVODeallocateBreak to stop here in the debugger. Here's the current observation info:
<NSKeyValueObservationInfo 0x109429cc0> (
<NSKeyValueObservance 0x109429c50: Observer: 0x10942d1c0,Key path: name,Options: <New: NO,Old: NO,Prior: NO> Context: 0x0,Property: 0x10968fa00>
)

在单元格中,当模型属性设置/更改时,我执行此操作：

[_model addObserver:self
         forKeyPath:@"name"
            options:0
            context:nil];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(modelIsInvalid:)
                                             name:@"modelIsInvalid"
                                           object:_model];

然后在单元格的dealloc中：

- (void)dealloc
{
    NSLog(@"DEALLOC CELL");
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    [_model removeObserver:self forKeyPath:@"name"];
}

在模型中,我还检查它什么时候被释放：

- (void)dealloc
{
    NSLog(@"DEALLOC MODEL");
}

所有单元格在所有模型之前被释放,但是我仍然收到这个错误.另外我不知道如何设置错误中提到的断点.