記得老早以前就看到有人把反射稱之為“性能殺手",正好目前正在做的erp系統為了實現擴展，系統就是架構在反射的基礎之上，數據交互也都是通過反射來實現。首先系統會產生太多dll,現在剛剛起步，已經高達43個之多，由于erp系統具有很復雜的業務功能，產品在發布階段很可能產生200甚至更多的dll，且不說這幾百個項目在調試的時候，漫長的等待是多么的痛苦，在產品推出去之后，這么多的dll的版本如何維護？多現在為止，除了windows還沒有見過dll超過百的系統，難道我們的系統真的比windows還要難？這些暫且不提，先測試一下反射在系統應用的性能情況，測試程序如下:

//被測試類
using System;
using System.Collections.Generic;
using System.Text;

namespace ClassLibrary1
{
    public class CTester
    {
        public CTester()
        {
            a = 10;
        }


        public void test1()
        {
            a = (a - 0.0001) * 1.0001;
        }
        private double a;
        public double geta() { return a; }
    }
}


/**////測試類
using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.Collections;

namespace ConsoleApplication2
{
   
        public class CTester
        {
            public CTester()
            {
                a = 10;
            }
        

            public void test1()
            {
                a = (a - 0.0001) * 1.0001;
            }
            private double a;
            public double geta() { return a; }
        }

   


    class Program
    {
        private string test1()
        {
            int now = System.Environment.TickCount;
           
            for (int i = 0; i < 1000; i++)
            {
                for (int j = 0; j < 100; j++)
                {
                    CTester aTest = new CTester();
                    aTest.test1();
                    
                }
            }

            string time = (System.Environment.TickCount - now).ToString();
            return time;
        }
        static Hashtable table = new Hashtable();
        private string test3()
        {
            int now = System.Environment.TickCount;
           
            for (int i = 0; i < 1000; i++)
            {
                for (int j = 0; j < 100; j++)
                {
                    Type theTest = null;
                    if (table.ContainsKey("ConsoleApplication2.CTester"))
                    {
                        theTest = table["ConsoleApplication2.CTester"] as Type;
                    }
                    else
                    {
                        theTest = Type.GetType("ConsoleApplication2.CTester");
                        table.Add("ConsoleApplication2.CTester", theTest);
                    }
                    ConsoleApplication2.CTester theobj = theTest.InvokeMember(null, BindingFlags.CreateInstance
                        , null, null, null) as ConsoleApplication2.CTester;
                    theobj.test1();
                }
            }

            string  time =(System.Environment.TickCount - now).ToString();
            return  time;
        }
        private string test2()
        {
            int now = System.Environment.TickCount;
            for (int i = 0; i < 1000; i++)
            {
                for (int j = 0; j < 100; j++)
                {
                    Type theTest = theTest = Type.GetType("ConsoleApplication2.CTester"); ;
                    ConsoleApplication2.CTester theobj = theTest.InvokeMember(null, BindingFlags.CreateInstance
                        , null, null, null) as ConsoleApplication2.CTester;
                    theobj.test1();
                }
            }

            string  time =(System.Environment.TickCount - now).ToString();
            return time;
        }
          static object InvokeMehod(string FileName,
            string MethodName,
            object[] Args)
        {
            Assembly a = Assembly.LoadFrom(FileName);


            MethodInfo method = null;
            Type HereType = null;
            foreach (Module m in a.GetModules())
            {
                foreach (Type t in m.GetTypes())
                {

                    foreach (MethodInfo mInfo in t.GetMethods())
                    {
                        if (mInfo.Name == MethodName)
                        {
                            ParameterInfo[] pInfo = mInfo.GetParameters();
                            if (pInfo.Length == Args.Length)
                            {
                                bool same = true;
                                for (int i = 0; i < pInfo.Length; i++)
                                {
                                    if (Args[i] != null && pInfo[i].ParameterType != typeof(object)
                                        && pInfo[i].ParameterType != typeof(object[]))
                                    {
                                        if (pInfo[i].ParameterType != Args[i].GetType())
                                        {
                                            same = false;
                                        }
                                    }
                                }
                                if (same)
                                {
                                    HereType = t;
                                    method = mInfo;
                                }
                            }
                        }

                        if (method != null)
                        {
                            break;
                        }
                    }

                    if (method != null)
                    {
                        break;
                    }
                }

                if (method != null)
                {
                    break;
                }
            }

            if (method == null)
            {
                //Log.LogException(typeof(Excute), "沒有發現：" + FileName + "/" + MethodName, new Exception("沒有發現：" + FileName + "/" + MethodName));
                return null;
            }

            object ins = null;
            if (!method.IsStatic)
            {
                ins = a.CreateInstance(HereType.FullName);
            }
            object RetObject = method.Invoke(ins, Args);
            return RetObject;
        }
    

        private string test5()
        {
            int now = System.Environment.TickCount;
            for (int i = 0; i < 1000; i++)
            {
                for (int j = 0; j < 100; j++)
                {
                    InvokeMehod(@"D:\ConsoleApplication2\ConsoleApplication2\ConsoleApplication2\bin\Debug\ClassLibrary1.dll", "test1", new object[] { });
                }
            }

            string time = (System.Environment.TickCount - now).ToString();
            return time;
        }
        static void Main(string[] args)
        {
            Program p = new Program();
            string ticks = p.test1();
            Console.WriteLine("用編譯器執行:"+ticks);
            string t = p.test2();
            Console.WriteLine("用反射執行"+t);
            string t1 = p.test3();
            Console.WriteLine("優化之后的反射:"+t1);
            string t2 = p.test5();
            Console.WriteLine("加載程序集并反射:"+t2);
            if (ticks.ToString() == "0")
            {
                Console.WriteLine("反射/編譯: 不在一個級別上面");
            }
            else
            {
                Console.WriteLine("反射/編譯 =" + (Convert.ToInt32(t) / Convert.ToInt32(ticks)).ToString());
            }
     
            if (ticks.ToString() == "0")
            {
                Console.WriteLine("加載程序集并反射/編譯: 不在一個級別上面");
            }
            else
            {
                Console.WriteLine("加載程序集并反射/編譯 =" + (Convert.ToInt32(t2) / Convert.ToInt32(ticks)).ToString());
            }
           

            Console.WriteLine("加載程序集并反射/反射 =" + (Convert.ToInt32(t2) / Convert.ToInt32(t)).ToString());
           
            Console.Read();
        }
    }
}

測試結果為:

638倍的性能損失，不知道算大算小，反正項目經理說無所謂。
赫赫，無（。。）者無畏