C#反射之使用绑定句柄减少进程的内存消耗

最近在看反射方面的东西的时候，看到最后发现一个与内存优化相关的东西，在此记录一下:

以下是文中介绍的 MethodInfo 和 RuntimeMethodHandle 相互转换测试代码:

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;

namespace GenDLL
{
    class Class1
    {
        const BindingFlags bFlags = BindingFlags.FlattenHierarchy | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
        public static void Main(string[] args)
        {
            //显示在任何反射操作之前的堆栈的大小
            Show("Before doing anying");

            //为MSCorlib.dll中的所有方法构建 MethodInfo 对象缓存
            List<MethodBase> methodInfoList = new List<MethodBase>();
            //遍历定义  Object 类的程序集中定义的公共类型
            foreach (Type type in typeof(Object).Assembly.GetExportedTypes())
            {
                //过滤任何泛型的类型
                if (type.IsGenericTypeDefinition) continue;
                MethodBase[] array = type.GetMethods(bFlags);
                methodInfoList.AddRange(array);
            }

            //显示当绑定所有方法之后，方法的个数和堆的大小
            Console.WriteLine("# of method = {0:N0} ", methodInfoList.Count);
            Show("After building cache of MethodInfo Object");

            //为所有的 MethodInfo 对象构建 RuntimeMethodHandle缓存
            List<RuntimeMethodHandle> methodHandles = methodInfoList.ConvertAll<RuntimeMethodHandle>(mb => mb.MethodHandle);
            Show("Holding MethodInfo and RuntimeMethodHandle of cache");
            GC.KeepAlive(methodInfoList);   //阻止缓存被过早的回收
            methodInfoList = null;          //现在允许进行回收
            Show("After free MethodInfo Objects");

            methodInfoList = methodHandles.ConvertAll<MethodBase>(rmh => MethodBase.GetMethodFromHandle(rmh));                  //方式一
            // methodInfoList = methodHandles.ConvertAll<MethodBase>(rmh => { return MethodBase.GetMethodFromHandle(rmh); });   //方式二
            Show("Size of heap  After re-creating MethodInfo Objects");

            GC.KeepAlive(methodInfoList);   //阻止缓存被过早的回收
            GC.KeepAlive(methodHandles);    //阻止缓存被过早的回收

            methodInfoList = null;
            methodHandles = null;

            Show("After freeing  MethodInfos and RuntimeMethodHandles");

            Console.ReadLine();
        }

        static void Show(string str)
        {
            //用逗号隔开的数字，0 表示占位符   12:N0 表示用逗号分隔数字，至少占12个字符，小数点后的位数为0
            string format = "Heap Size = {0,12:N0} - {1}";
            Console.WriteLine(format, GC.GetTotalMemory(true), str);
        }
    }
}

编程小知识之 GC.KeepAlive ：https://blog.csdn.net/tkokof1/article/details/92073033