复制具有引用类型作为成员的值类型

Question

如果我复制具有引用类型成员（在我的例子中是字符串）的值类型，CLR 会进行浅表复制 (book)。所以我写了一个小程序只是为了实验但无法得到预期的结果。我确定我在这里遗漏了一些细节。

public class Program
{
    public static void Main(string[] args)
    {
        Console.WriteLine("First Example");
        //first example
        Point p1 = new Point();
        p1.Name = "firstPoint";
        p1.X = 10;
        p1.Y = 20;

        Point p2 = p1;

        p2.Name = "secondPoint";
        p2.X = 40;
        p2.Y = 50;

        p1.Print(); //Prints - Name: firstPoint, X:10, Y:20
                    //Expected - Name: secondPoint, X:10, Y:20
        p2.Print(); //Prints - Name: secondPoint, X:40, Y:50

        Console.ReadLine();
    }
}

public struct Point
{
    public string Name;
    public int X;
    public int Y;

    public void Print()
    {
        Console.WriteLine("Name: {0}, X: {1}, Y: {2}", this.Name.ToString(), this.X, this.Y);
    }
}

Answer 1

您已经更改了整个引用类型，因此它的行为就像那样，您可以尝试更改该引用类型的成员以验证和解决它。

参考以下代码：

public class Program
{
    public static void Main()
    {
        Console.WriteLine("First Example");
        //first example
        Point p1 = new Point();
        p1.store = new SomeClass();
        p1.store.Name = "Jenish";
        p1.Name = "firstPoint";
        p1.X = 10;
        p1.Y = 20;

        Point p2 = p1;

        p2.Name = "secondPoint";
        p2.store.Name = "Jenish2";
        p2.X = 40;
        p2.Y = 50;

        p1.Print(); //Prints - Name: firstPoint, X:10, Y:20
        p2.Print(); //Prints - Name: secondPoint, X:40, Y:50

        Console.ReadLine();
    }
}

public struct Point
{
    
    public string Name;
    public int X;
    public int Y;
    public SomeClass store;

    public void Print()
    {
        Console.WriteLine("Name: {0}, X: {1}, Y: {2}, Name: {3}", this.Name.ToString(), this.X, this.Y, this.store.Name);
    }
}

public class SomeClass{
    public string Name {get; set;}
}

输出

First Example

Name: firstPoint, X: 10, Y: 20, Name: Jenish2

Name: secondPoint, X: 40, Y: 50, Name: Jenish2

这是给你的 fiddle。

下面的示例演示了当您更改整个引用类型时会发生什么情况。

public class Program
{
    public static void Main()
    {
        Console.WriteLine("First Example");
        //first example
        Point p1 = new Point();
        p1.store = new SomeClass();
        p1.store.Name = "Jenish";
        p1.Name = "firstPoint";
        p1.X = 10;
        p1.Y = 20;

        Point p2 = p1;

        p2.Name = "secondPoint";
        p2.store = new SomeClass();
        p2.store.Name = "Jenish2";
        p2.X = 40;
        p2.Y = 50;

        p1.Print(); //Prints - Name: firstPoint, X:10, Y:20
        p2.Print(); //Prints - Name: secondPoint, X:40, Y:50

        Console.ReadLine();
    }
}

public struct Point
{
    
    public string Name;
    public int X;
    public int Y;
    public SomeClass store;

    public void Print()
    {
        Console.WriteLine("Name: {0}, X: {1}, Y: {2}, Name: {3}", this.Name.ToString(), this.X, this.Y, this.store.Name);
    }
}

public class SomeClass{
    public string Name {get; set;}
}

注意：两个对象的名称不同。

这是第二个例子fiddle。

复制具有引用类型作为成员的值类型

copying a value type that has reference type as a member

c#

value-type

reference-type