Cocoa KVC：“类不是关键值编码兼容” [英] Cocoa KVC: "class is not key value coding-compliant"

问题描述

我想用KVC更新一些属性。

I'm trying to update some properties with KVC. The properties have been synthesized.

此行适用于：

myObject.value = intValue;

这不起作用：

[self setValue:[NSNumber numberWithInt:intValue] forKey:@"myObject.value"];

并且爆炸：由于未捕获异常NSUnknownKeyException终止应用程序，原因： [< MyViewController 0xd1cec0> setValue：forUndefinedKey：]：此类不是键myObject.value的键值编码。

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.'

（awakeFromNib）相同类的其他实例响应正确setValue：forKey：调用。唯一的区别是这个特定的实例是在IB中创建和连接的。

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.

推荐答案

它告诉你那个对象不是一个有效的键，事实上它不是：myObject.value 是一个键，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.

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