按值或在C#中通过引用 [英] by value or by reference in c#

问题描述

你好，

我在c#中创建了一个类:

Hello,

I created a class in c#:

public myClass()
{
  .....
}

1)如果我像这样分配课程:

1) If I assign the class like this:

myClass m1 = new myClass();
....
myClass m2 = m1;

是将m1(按值)复制到m2，还是通过引用进行分配?

2)我创建了一个ArrayList.
如果我将myClass的实例添加到ArrayList中，将按值(副本)还是按引用添加它?

谢谢

will m1 be copied (by value) to m2, or will it be assigned by reference?

2)I created an ArrayList.
If I add an instance of myClass to the ArrayList, will it be added by value (copy) or by reference?

Thanks

推荐答案

如果是类，它将由ref分配:)

If it is class, it will be assigned by ref :)

类始终是引用(结构是Value)类型和引用始终是引用的副本，而不是类本身内的值，除非创建了副本构造函数并明确使用:

Classes are always References (structs are Value types) and References are always copies of the reference, not the values within the class itself unless a copy constructor is created, and used explicitly: http://msdn.microsoft.com/en-us/library/ms173116(v=vs.80).aspx[^]

So an assignment of a reference value to another reference variable will always result in two references that "point" at the same data instance:

MyClass m1 = new MyClass();
m1.Name = "Joe";
MyClass m2 = m1;
Console.WriteLine (m1.Name + " = " + m2.Name);
m1.Name = "Mike";
Console.WriteLine (m1.Name + " = " + m2.Name);

将输出:

Will output:

Joe = Joe
Mike = Mike

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