测试使用的环境：vs2019+.net core3.1

原文地址：https://www.cnblogs.com/hhhnicvscs/p/14296715.html

反驳第一条：如何检查代码中的空字符串?

调整顺序后输出，如下图：

上图调整顺序后，发现耗时排序发生了逆转。为什么？自行研究。

using System;
using System.Diagnostics;

namespace ConsoleApp1
{
    public class Compare
    {
        public static void First(string Value)
        {
            if (Value.Length != 0)
            {
            }
        }
        public static void Second(string Value)
        {
            if (Value != "")
            {
            }
        }
        public static void Third(string Value)
        {
            if (Value != string.Empty)
            {
            }
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Stopwatch sw = new Stopwatch();
            sw.Start();
            Compare.Third("weuroovnuifbbno");
            sw.Stop();
            Console.WriteLine("Using Empty: " + sw.ElapsedTicks);
            sw.Restart();
            Compare.Second("weuroovnuifbbno");
            sw.Stop();
            Console.WriteLine("Using !=     " + sw.ElapsedTicks);
            sw.Restart();
            Compare.First("weuroovnuifbbno");
            sw.Stop();
            Console.WriteLine("Using Length: " + sw.ElapsedTicks);
            
            Console.WriteLine("---------------");


            sw.Restart();
            Compare.First("joigjoerjgiogro");
            sw.Stop();
            Console.WriteLine("Using Length: " + sw.ElapsedTicks);
            sw.Restart();
            Compare.Second("joigjoerjgiogro");
            sw.Stop();
            Console.WriteLine("Using !=     " + sw.ElapsedTicks);
            sw.Restart();
            Compare.Third("joigjoerjgiogro");
            sw.Stop();
            Console.WriteLine("Using Empty: " + sw.ElapsedTicks);

            Console.ReadLine();
        }
    }
}