Cocoa KVC：“类不符合键值编码”
我正在尝试使用 KVC 更新一些属性。 属性已被合成。
此行有效：
myObject.value = intValue;
这行不通：
[self setValue:[NSNumber numberWithInt:intValue] forKey:@"myObject.value"];
并崩溃： 由于未捕获的异常“NSUnknownKeyException”而终止应用程序，原因：“[
进一步，同一类的方法 (awakeFromNib) 的其他实例对 setValue:forKey: 调用响应良好。 唯一的区别是这个特定实例是在 IB 中创建和连接的。
I'm trying to update some properties with KVC. The properties have been synthesized.
This line works:
myObject.value = intValue;
This doesn't work:
[self setValue:[NSNumber numberWithInt:intValue] forKey:@"myObject.value"];
And blows up with: Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<MyViewController 0xd1cec0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key myObject.value.'
Yet further up the method (awakeFromNib) other instances of the same class respond fine to setValue:forKey: calls. The only difference is this particular instance was created and wired up in IB.
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评论（3）
您不能将键路径作为第二个参数传递给
-[NSObject setValue:forKey:]。 您想使用setValue:forKeyPath:代替：我的理解是
setValue:forKey:是作为性能优化而提供的。 由于它不能采用密钥路径，因此它不必解析密钥字符串。You cannot pass a key path as the second argument to
-[NSObject setValue:forKey:]. You want to usesetValue:forKeyPath:instead:My understanding is that
setValue:forKey:is provided as a performance optimization. Since it cannot take a key path, it doesn't have to parse the key string.它告诉您这不是该对象的有效键，实际上也不是：“myObject.value”是一个键路径，而不是单个键。
It's telling you that isn't a valid key for that object, and indeed it isn't: "myObject.value" is a keypath, not a single key.
我同意查克的观点。
我认为你需要这样做：
或者通过关键路径的每个部分，例如：
I agree with Chuck.
I think you need to do this instead:
or via each part of the key path like: