用点或括号语法设置属性之间有区别吗? [英] Is there a difference between setting a property with the dot or the bracket syntax?

问题描述

鉴于下面的属性声明，方法(A)的工作方式与方法(B)完全相同吗?我只想检查self.yellowViewController = yellcon_New;正在通过我的设置器，以便释放旧对象并保留新对象.

Given the property declaration below, does method (A) work in exactly the same way as method (B)? I just want to check that self.yellowViewController = yellcon_New; is going via my setter, so that the old objects gets released and the new one retained.

// INTERFACE
@property(nonatomic, retain) YellowViewController *yellowViewController;

// IMPLEMENTATION (A)
self.yellowViewController = yellcon_New;

// IMPLEMENTATION (B)
[self setYellowViewController:yellcon_New];

推荐答案

所有这些都是正确的:

self.yellowViewController = yellcon_New;

还有

[self setYellowViewController:yellcon_New];

工作相同. 我想添加一些有趣的东西:当您使用

Work the same. I would like to add something interesting : when you use

yellowViewController = yellcon_New;

您可以直接将值关联到ivar，而无需通过设置方法.

you associate directly the value to the ivar, without going through your setter methode.

如果有的话

-(void)setYellowViewController:(YellowViewController*)theYellowViewController;
{
    NSLog(@"Setting the yellow view controller");
    [yourWife askFor:beer];
    ...whatever...
    ...set the yellowViewController (retain in your case)
}

通话

self.yellowViewController = yellcon_New;

和

[self setYellowViewController:yellcon_New];

将使用setter方法(并记录消息，并让您的妻子为您带来一些啤酒)

will use the setter method (and log the message, and make your wife bring you some beer)

但是

yellowViewController = yellcon_New;

不会.

在某些情况下知道这一点很有趣.

It's interesting to know this in some cases.

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