性能 - 通过值或引用？ [英] Properties - by value or reference?

问题描述

我有这暴露了一个的ArrayList 以下公共财产：

I've got the following public property which exposes an Arraylist:

public ArrayList SpillageRiskDescriptions
        {
            get
            {
                return _SpillageRiskDescriptions;
            }
            set
            {
                _SpillageRiskDescriptions = value;
            }
        }

在其他地方我打电话

Elsewhere I'm calling

SpillageRiskDescriptions.Add("VENTILATE AREA");
SpillageRiskDescriptions.Add("DO NOT ALLOW SPILLAGE TO ENTER MAINS");

这些似乎（通过属性）来将元素添加到私人的ArrayList _SpillageRiskDescriptions 而我会一直期待这会导致一个问题。所以我是正确的思想，属性返回一个引用以原始变量，而不是通过的价值传递给它？这是因为的ArrayList 是引用类型？将在同一个发生在一个 INT （比如？）

These seem to be adding elements to the private ArrayList _SpillageRiskDescriptions (through the property) whereas I would've expected this to cause a problem. Therefore am I correct in thinking that properties return a reference to the original variable and not passing it by value? Is this because ArrayList is a reference type? Will the same happen with an int (for example?)

推荐答案

从技术上讲，它总是由价值，但你要明白什么是被通过。因为它是一个引用类型，你传递一个参考回（但按价值计算）。

Technically it's always by value, but you have to understand what is being passed. Since it's a reference type, you are passing a reference back (but by value).

希望是有道理的。你总是通过的结果回值，但如果类型是引用您传递基准回值，这意味着你可以改变的对象，而不是哪个对象是指。

Hope that makes sense. You always pass the result back by value, but if the type is a reference you are passing the reference back by value, which means you can change the object, but not which object it refers to.

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