test for existence of key
Does iPhone key-value-coding have a way to test whether a class will accept a given key?
That is, without implementing the valueForUndefinedKey: or setValue: forUndefinedKey: method of the target class, I want to be able to do something like this:
if ([targetObject knowsAboutKey: key]) {
[targetObject setValue: value forKey: key];
}
The default implementation of setValue:forUndefinedKey: raises an NSUndefinedKeyException. You could surround the attempt in a try/catch block:
@try{
[targetObject setValue:value forKey:key];
} @catch (NSException *e) {
if ([[e name] isEqualToString:NSUndefinedKeyException]) {
NSLog(@"oh well... handle the case where it has no key here."); // handle
} else {
[[NSException exceptionWithName:[e name]
reason:[e reason]
userInfo:[e userInfo]]
raise];
}
}
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