C#，反射和直接调用的效率差别

反射时，由于编译器要判断权限，身份等操作，所以比直接操作要慢

 

测试代码：

            const int NUM = 1000000;

            Stopwatch sw = new Stopwatch();
            sw.Start();

            for (int i = 0; i < NUM; i++)
            {
                ReflectTest rt = new ReflectTest();
                rt.CountSomething();
            }

            sw.Stop();
            Console.WriteLine(sw.ElapsedTicks);


            sw.Reset();
            sw.Start();
            for (int i = 0; i < NUM; i++)
            {
                Assembly assembly = Assembly.GetExecutingAssembly();
                Type t = assembly.GetType("ConsoleApplication1.ReflectTest");
                ConstructorInfo constructorInfo = t.GetConstructors().OrderBy(c => c.GetParameters().Length).FirstOrDefault();
                object obj = constructorInfo.Invoke(new object[constructorInfo.GetParameters().Length]);
                //object obj = Activator.CreateInstance(t);
                MethodInfo methodInfo = t.GetMethod("CountSomething");
                methodInfo.Invoke(obj,new object[methodInfo.GetParameters().Length]);
            }
            sw.Stop();
            Console.WriteLine(sw.ElapsedTicks);



            Console.ReadKey();

 

 

结果：

 

 

反射用时是直接调用的2到3倍，所以非特殊需求，项目中就不要用反射吧。。。