从程序结果分析对象上转型

//person.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
class person
{
public int Age = 24;
public String Name = "cheng.cheng";
}
}
//Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
class Program
{
private int TestA = 0;
static void Main(string[] args)
{
Console.WriteLine("Int:");
int a = 1;
object objectA = (Object)a;
a = 2;
Console.WriteLine("a=" + a + ",objectA=" + objectA);
Console.ReadLine();
Console.WriteLine("String:");
string strA = "abc";
object objectStra = (Object)strA;
strA = "abcdefg";
Console.WriteLine("strA=" + strA + ",objectStra=" + objectStra);
Console.ReadLine();
Console.WriteLine("Object:");
object objecta1 = "123";
string stra1 = (string)objecta1;
objecta1 = "123456";
Console.WriteLine("stra1=" + stra1 + ",objecta1=" + objecta1);
Console.ReadLine();

Console.WriteLine("Class:");
person p = new person();
Object objectP = p;
person pp = (person)objectP;
p.Age = 20;
p.Name = "LiMing";
Console.WriteLine("p.Age=" + p.Age + ",objectP.Age=" + pp.Age);
Console.WriteLine("p.Name=" + p.Name + ",objectP.Name=" + pp.Name);
Console.ReadLine();

Program Program = new Program();
Console.WriteLine(Program.TestA);
Console.ReadLine();

}
}
}

输出结果：

Int:
a=2,objectA=1

String:
strA=abcdefg,objectStra=abc

Object:
stra1=123,objecta1=123456

Class:
p.Age=20,objectP.Age=20
p.Name=LiMing,objectP.Name=LiMing

说明：

1、上转型时对于值类型和String Object是要重新分配空间的。

2、对于Calss对象则是引用地址。

3、上转型是一种特殊的赋值,由此推论到任意赋值遵守1、2两条。