if (Object.ReferenceEquals(str1,str2))

using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;namespace ConsoleApplication9
 {
     class Program
     {
         static void Main(string[] args)
         {
             Program a = new Program();
             Program b = new Program();
             if (a.Equals(b))
             {
                 Console.WriteLine("a=b");
             }
             Console.WriteLine("a:{0}", a.GetHashCode());
             Console.WriteLine("b:{0}", b.GetHashCode());
             Program c = a;
             if (a.Equals(c))
             {
                 Console.WriteLine("a=c");
             }
             String str1 = new String("Hello".ToCharArray());
             String str2 = new String("Hello".ToCharArray());
             if (str1.Equals(str2))
             {
                 Console.WriteLine("str1=str2");
             }
             if (str1==str2)
             {
                 Console.WriteLine("str1=str2");
             }
             Console.WriteLine("str1:{0}", str1.GetHashCode());
             Console.WriteLine("str2:{0}", str2.GetHashCode());
             if (Object.ReferenceEquals(str1,str2))
             {
                 Console.WriteLine("Object.ReferenceEquals(str1,str2)");
             }
             else
             {
                 Console.WriteLine("Object.Reference not Equals(str1,str2)");
             }        }
     }
 }
 /*
 a:46104728
 b:12289376
 a=c
 str1=str2
 str1=str2
 str1:-694847
 str2:-694847
 Object.Reference not Equals(str1,str2)
 请按任意键继续. . .
  */