测试C# 类型转换效率问题

using System;

using System.Diagnostics;

 

namespace TestTypeChange

{

  public class MyClass{

      public int id = 0;

      public string name = "";

      public MyClass(int _id,string _name){

          id = _id;

          name = _name;

      }

  }

 

  class MainClass

  {

      public static void Main (string[] args)

      {

          Stopwatch stopwatch;

          object obj_ptr = null;

          MyClass myclass = new MyClass (0, "cjane");

          MyClass ref_myclass = null;

          int count = 100000000;

 

          stopwatch = Stopwatch.StartNew();

          for (int i = 0; i < count; i++)

              ref_myclass = myclass;

          stopwatch.Stop();

          Console.WriteLine("class to class: " + stopwatch.Elapsed);

 

          stopwatch = Stopwatch.StartNew();

          for (int i = 0; i < count; i++)

              obj_ptr = myclass;

          stopwatch.Stop();

          Console.WriteLine("class to object: " + stopwatch.Elapsed);

 

 

          stopwatch = Stopwatch.StartNew();

          for (int i = 0; i < count; i++)

              ref_myclass = (MyClass)obj_ptr;

          stopwatch.Stop();

          Console.WriteLine("object to class: " + stopwatch.Elapsed);

 

          int val = 100;

          int cp_val = 0;

 

          stopwatch = Stopwatch.StartNew();

          for (int i = 0; i < count; i++)

              ref_myclass = myclass;

          stopwatch.Stop();

          Console.WriteLine("value to value: " + stopwatch.Elapsed);

 

          stopwatch = Stopwatch.StartNew();

          for (int i = 0; i < count; i++)

              obj_ptr = val;

          stopwatch.Stop();

          Console.WriteLine("value to object: " + stopwatch.Elapsed);

 

 

          stopwatch = Stopwatch.StartNew();

          for (int i = 0; i < count; i++)

              cp_val = (int)obj_ptr;

          stopwatch.Stop();

          Console.WriteLine("object to value: " + stopwatch.Elapsed);

 

      }

  }

}

 

 

 

测试结果：

    class to class: 00:00:00.3463484

    class to object: 00:00:00.3520921

    object to class: 00:00:00.3760758

    value to value: 00:00:00.3303531

    value to object: 00:00:01.9317834

    object to value: 00:00:00.3482110    

 

 

测试得出C# 引用类型间的转换几乎和赋值时候差不多，性能损耗几乎忽略不计

但如果是整型值类型间的转换，把整型值类型转为object的时候，性能比较低

有兴趣的可以试试下字符串与object间的转换