如果字符串是引用类型，为什么在这种情况下 strA 的值没有改变？

Question

我以为我理解了引用类型和值类型之间的区别。我认为 'string' 只有值类型 语义 同时保留了引用类型的行为。然后我尝试了这个，希望在两种情况下都能看到 True 返回。 我误会了什么？

        string strA = "AAA";
        string strB = strA;
        strB = "BBB";
        Console.WriteLine($"strA is {strA} and strB is {strB}");
        Console.WriteLine($"The statement: strA == strA is {strA == strB} \n");

        Car car1 = new Car();
        car1.Horsepower = 190;
        Car car2 = car1;
        car2.Horsepower = 200;
        Console.WriteLine($"car1.Horsepower is {car1.Horsepower} and car2.Horsepower is {car2.Horsepower}");
        Console.WriteLine($"The statement: car1 == car2 is {car1 == car2}");

输出：

strA is AAA and strB is BBB

The statement: strA == strA is False

car1.Horsepower is 200 and car2.Horsepower is 200

The statement: car1 == car2 is True

Answer 1

字符串文字指定字符串实例。将字符串转换为汽车以方便使用，这基本上就是您使用字符串所做的事情：

Car AAA = new Car();
Car BBB = new Car();

Car carA = AAA;
Car carB = carA;
carB = BBB;
Console.WriteLine($"carA is {carA} and carB is {carB}");
Console.WriteLine($"The statement: carA == carB is {carA == carB}

最大的区别在于您使用 "string literals" 而不是 new Car/new String，因为编译器会为静态字符串预先分配对象。