This class is not key value coding-compliant for the key Picker

问题

I added a view to my app that I open from a button and can't find what I'm doing wrong.

I triple checked that dataSource & delegate are connected to File's Owner

*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<HelpViewController 0xab58980> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key Picker.'

The code in my viewcontroller.h

@interface LanguageSelectionViewController : UIViewController {

    IBOutlet UILabel *label;
    IBOutlet UIPickerView *Picker;
    NSArray *PickerData;
}

@property (retain, nonatomic) IBOutlet UIPickerView *Picker;
@property (retain, nonatomic) NSArray *PickerData;
@end

Anyone got a solution or a tip in the right direction?

回答1:

Go to your storyboard click the helpviewcontroller (the whole thing so you have a blue outline around the view) now with the utility toolbar (toolbar on the right) click the arrow (the right most icon) you should see a ! mark on one of the connections. Delete that and it should work.

来源：https://stackoverflow.com/questions/17814389/this-class-is-not-key-value-coding-compliant-for-the-key-picker