Objective-C：何时调用self.myObject vs只调用myObject [英] Objective-C: When to call self.myObject vs just calling myObject

问题描述

在Objective-C中，这一点语法对我来说有点混乱。

This little bit of syntax has been a bit of a confusion for me in Objective-C.

我什么时候应该调用self.myObject vs只调用myObject？

When should I call self.myObject vs just calling myObject?

这似乎是多余的，但它们不可互换。

It seems redundant however they are not interchangeable.

有人可以开导我吗？

推荐答案

如果您只是访问它们，则没有太多理由使用 self.member 。如果你正在进行任务，那么你做的不仅仅是简单的 @property（assign）参数 - 例如，保留，复制等，所以它可以节省您正在编写的代码。例如：

If you're just accessing them, there's not much reason to use self.member. If you're doing assignment, it's good if you're doing more than the simple @property (assign) parameter--for instance, retain, copy, etc, so it can save on code you're writing. An example:

myObject = anotherObject;
self.myObject = anotherObject;

第二个选择将确保您实际按照自己的方式分配对象（获取副本） ，增加保留计数等）。它与 [self setMyObject：anotherObject] 没有区别。

The second choice will ensure that you're actually assigning the object the way you want (getting a copy, increasing the retain count, etc.). It's no different from [self setMyObject:anotherObject].

由于点符号被替换为消息编译器（类似于 x [5] 如何在常规中变为 *（x + 5 * sizeof（x））数组工作），使用点符号比常规消息没有开销或额外的效率。

Since the dot-notation gets substituted for a message by the compiler (similar to how x[5] becomes *(x + 5*sizeof(x)) in regular array work), there's no overhead or extra efficiency in using dot-notation over regular messages.

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