c# 装箱子,开箱(inboxing,unboxing)

using System;
public class Inboxing
{
  static void Main(){
   int x=10;
   object ōbj=x;   //装箱, 将int的值赋给对象obj.
   if (obj is int){
   Console.WriteLine("the x value is inboxing");
  
   }
   x=20;  //x已经被声明过了, 所以这里不用再写成int x=20;
   Console.WriteLine("int: {0}",x);
   Console.WriteLine("object: {0}",obj);
   }
}

开箱:

using System;
public class Outboxing
{
  static void Main(){
   int x=10;
   object ōbj=x;
   int j=(int)obj; //开箱, 先将obj转换成int, 再将其赋给j. 这里不能写成 int j=obj, 这样会有错误的抛出: error CS0266: Cannot implicitly convert type 'objec 'int'. 

   if (obj is int){
   Console.WriteLine("the x value is inboxing");
  
   }
  
   x=20;
   Console.WriteLine("int: {0}",x);
   Console.WriteLine("object: {0}",obj);
   Console.WriteLine("j:{0}",j);
   }
}