1.         问题

请计算下列代码执行所耗费的时间，给出通用的解决方法？

List<Int32> myList=new List<Int32>();

          for(Int32 i=0;i<ICount;i++)

          {

          myList.Add(i);

          }

2.         解决方法

using (OperationTimer op=new OperationTimer ("Generic "))

{

                            List<Int32> myList=new List<Int32>();

                            for(Int32 i=0;i<ICount;i++)

                            {

                                     myList.Add(i);

                            }

                            }

}

OperationTimer 类会在调用构造函数时取得时间t1,在调用Dispose（）取得时间t2,中间过程耗费的时间=t2-t1. Using 语法会在using 块的末尾调用using中声明对象的Dispose方法。

3.         代码

using System;

using System.Diagnostics;

using System.Collections;

using System.Collections.Generic;

namespace genericApp

{

    ///计时辅助类

         public class OperationTimer:IDisposable{

                   private Int64 m_startTime;

                   private string m_text;

                   private Int32 m_CollectionCount;

                   public OperationTimer(string text)

                   {

                            m_startTime=Stopwatch.GetTimestamp();

                            m_text=text;

                   }

                   public void Dispose()

                   {

                            string text=string.Format("Time={0,6:###.00}",(Stopwatch.GetTimestamp()-m_startTime)/Stopwatch.Frequency);

                            Console.WriteLine(string.Format("{0}:{1}",m_text,text));

                   }

         }

         class MainClass

         {

                   public static void Main(string[] args)

                   {

                            ValueTypePerfermanceTest();

                            Console.Read();

                   }

                   static void ValueTypePerfermanceTest()

                   {

                            const Int32 ICount=20000000;

                            using (OperationTimer op=new OperationTimer ("Generic "))

                            {

                                     List<Int32> myList=new List<Int32>();

                            for(Int32 i=0;i<ICount;i++)

                            {

                                     myList.Add(i);

                            }

                            }

                            using (OperationTimer op2=new OperationTimer ("ArrayList "))

                            {

                                     ArrayList myList=new ArrayList();

                            for(Int32 i=0;i<ICount;i++)

                            {

                                     myList.Add(i);

                            }

                            }

                   }

         }

}

4.         Mono 2.4 中的运行结果