macOS NSButton question in cocoa

my codes:

IBOutlet NSButton* oneButton;

-(void) disableButton: (NSButton *) button{
[button setEnabled:NO];
}
-(IBAction) pressOneButton: (id) sender{

if([sender isEnabled] == YES){ // case 1
//do something;
}

if([oneButton isEnabled] == YES){ // case 2
//do something;
}
}

Obviously, I want to disable the button through the method disableButton. But unfortunately, case 1 doesn't work as my wish which case 2 does.

So, I'm puzzled. why the state of the 'sender' is different from the oneButton?

Oh, my God!

It's really that I forgot to bind the outlet to the component.....

Forgive this fool question..