不知道为什么出现异常
using System;
namespace _12._1._3可空类型的装箱拆箱
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("可空的类型的装箱拆箱如下:");
BoxdandUnboxed();
Console.Read();
}
public static void BoxdandUnboxed()
{
Nullable<int> nullable = 5;
int? nullablewithoutvale = null;
Console.WriteLine("获取不为null的可空类型为{0}",nullable.GetType());
Console.WriteLine("获取为null的可空类型为:{0}", nullablewithoutvale.GetType());
object obj = nullable;
Console.WriteLine("装箱后obj的类型为{0}",obj.GetType());
int value = (int)obj;
Console.WriteLine("拆箱后非可空变量的情况为{0}",value);
nullable = (int?)obj;
Console.WriteLine("拆箱后可空变量的情况为{0}",nullable);
obj = nullablewithoutvale;
Console.WriteLine("对null的可空类型装箱后obj是否为null:{0}",obj==null);
nullable = (int?)obj;
Console.WriteLine("一个没有值的可空类型装箱后,拆成可空变量是否为null:{0}",nullable==null);
}
}
}