值参数的意义在于传进来的参数是该参数的副本，在传进来之后进行的改变，不会影响到该该参数本身的值
class Program { static void Main(string[] args) { Student stu = new Student(); Acess ac = new Acess(); ac.Max(stu.Age); Console.WriteLine("{0},{1}",stu.GetHashCode(),stu.Age); } class Acess { public void Max(int a) { a =a+18; Console.WriteLine("{0},{1}",a.GetHashCode(),a); } } class Student { public int Age=10; } }
而引用类型的参数要加修饰符ref，而且传参数之前要明确的给这个参数赋值，传进来的参数是这个参数的地址值，不会创建该参数的副本，所以传进来的参数值发生了改变，那么本体也会被改变
class Program { static void Main(string[] args) { Student stu = new Student(); Acess ac = new Acess(); ac.Max(ref stu.Age); Console.WriteLine("{0},{1}",stu.GetHashCode(),stu.Age); } class Acess { public void Max(ref int a) { a =a+18; Console.WriteLine("{0},{1}",a.GetHashCode(),a); } } class Student { public int Age=10; } }
原文：https://www.cnblogs.com/zxbls/p/13127304.html