C# 修改引用类型对象不反映更改 [英] C# Modifying Reference Type Objects doesn't reflect changes

问题描述

我有这个 C# 代码:

I have this C# code:

int i = 20;

object t = i;

object r = t;

r = 100;

为什么此时 T 的值仍然是 20 而不是 100 ?

我认为 T 和 R 指向同一个位置，对它们中的任何一个进行更改都会相互影响...

I supposed T and R pointed to the same location and changes to any of them should affect each other...

我真的无法理解 Heap 中的引用类型是如何工作的，请帮帮我

I can't really understand how reference types work in the Heap, please help me

推荐答案

为什么此时 T 的值仍然是 20 而不是 100 ?

Why at this point, the value of T is still 20 and not 100 ?

因为你没有修改t.

您需要查找 "拳击".但是，您的代码中发生的事情是存储在 i 中的值 20 被装箱"，这意味着分配了一个新的引用类型对象，并且值 20 被复制到那个对象中.

You'll want to look up "boxing". But, what's going on in your code is that the value 20 stored in i is "boxed", which means a new reference type object is allocated and the value 20 is copied into that object.

当您分配 r = t 时，您将该装箱值的引用复制到 t.到目前为止，一切都很好.

When you assign r = t, you copy the reference of that boxed value to t. So far, so good.

但是，当您分配 r = 100; 时，您没有修改了装箱值.原始装箱值保持不变，但现在仅被 t 引用.

But, when you assign r = 100;, you have not modified the boxed value. The original boxed value remains the same, but now is referenced only by t.

赋值 r = 100 创建一个全新的装箱值，分配在堆上，并将对该对象的引用复制到变量 r 中.这对 t 没有影响，它仍然设置为 20 的第一个装箱值的引用.

The assignment r = 100 creates a whole new boxed value, allocated on the heap, and copies the reference to that object into the variable r. This has no effect on t, which remains set to the reference of the first boxed value of 20.

这篇关于C# 修改引用类型对象不反映更改的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！