C#基础语法：as 运算符使用实例

// cs_keyword_as.cs// The as operator.using System;class Class1{}class Class2{}class MainClass{  static void Main()  {    object[] objArray = new object[6];    objArray[0] = new Class1();    objArray[1] = new Class2();    objArray[2] = "hello";    objArray[3] = 123;    objArray[4] = 123.4;    objArray[5] = null;    for (int i = 0; i < objArray.Length; ++i)    {      string s = objArray[i] as string;      Console.Write("{0}:", i);      if (s != null)      {        Console.WriteLine("'" + s + "'");      }      else      {        Console.WriteLine("not a string");      }    }  }}//=============================================================// 0:not a string1:not a string2:'hello'3:not a string4:not a string5:not a string