Ios 如何从'；发送方'；对象

我在故事板场景中有一个

ui按钮。该按钮配置了用户定义的运行时属性“类型”（字符串）。当按下按钮时，电话响了

-（iAction）按按钮：（id）发送者

我能否从“发件人”访问用户定义的运行时属性
 是：

-(IBAction)pressedButton:(id)sender
{
    id value = [sender valueForKey:key];
}


请注意，您不能使用用户定义的运行时属性，，除非您将UIButton子类化并将其作为强属性添加，例如

@interface UINamedButton : UIButton
@property (strong) NSString *keyName;
@end

如果您设置了一个用户定义的运行时属性，而您还没有这样做，那么Xcode将很不幸地崩溃

然后你可以像这样得到这个值

-(IBAction)clicked:(UIControl *)sender
    {
    NSString *test = @"???";

    if ( [sender respondsToSelector:@selector(keyName)] )
            test = [sender valueForKey:@"keyName"];

    NSLog(@"the value of keyName is ... %@", test);

    // if you FORGOT TO SET the keyName value in storyboard, that will be NULL
    // if it's NOT a UINamedButton button, you'll get the "???"

    // and for example...
    [self performSegueWithIdentifier:@"idUber" sender:sender];
    // ...the prepareForSegue could then use that value in the button.

    // note that a useful alternative to
    // if ( [sender respondsToSelector:@selector(stringTag)] )
    // is... 
    // if ( [sender respondsToSelector:NSSelectorFromString(@"stringTag")] )
    }