C#的StringBuilder 以及string字符串拼接的效率对照

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("1000万次运算：");
            DateTime dt = DateTime.Now;
            xxx xxx=new xxx();
            const int testNum = 10000000;
            StringBuilder strbuilder = new StringBuilder();
            strbuilder.Append("M");
            for (int i = 0; i < testNum; i++)
            {
                strbuilder.Append(i.ToString(),0,i.ToString().Length);
                xxx.text = strbuilder.ToString();
                strbuilder.Remove(0, strbuilder.Length-1);
            }
            Console.WriteLine("StringBuilder：" + (DateTime.Now - dt).Ticks);
            Console.WriteLine("\r\n");

            strbuilder.Remove(0, strbuilder.Length);
            strbuilder.Clear();
            strbuilder = null;
            dt = DateTime.Now;
            for (int i = 0; i < testNum; i++)
            {
                xxx.text = i+"M";
            }
            Console.WriteLine("String拼接：" + (DateTime.Now - dt).Ticks);
            Console.WriteLine("\r\n");


            dt = DateTime.Now;
            for (int i = 0; i < testNum; i++)
            {
                xxx.text = string.Format("%Sm", i.ToString());
            }
            Console.WriteLine("String.Format拼接：" + (DateTime.Now - dt).Ticks);
            Console.ReadLine();
        }
    }
    public class xxx
    {
        public string text { get; set; }
    }