Example use "System.Text.StringBuilder" in .NET framework by C# language

StringBuilder.cs

using System;
using System.Diagnostics;
using System.Text;
 
namespace StringBuilder
{
    class Program
    {
        static void Main(string[] args)
        {
            // ใช้ + ธรรมดาที่นิยมใช้กัน
            Stopwatch sw1 = new Stopwatch();
            string fooString1 = String.Empty;
            sw1.Start();
            for (int i = 0; i < 10000; i++)
            {
                fooString1 += i.ToString();
            }
            sw1.Stop();
            string sw1time = sw1.ElapsedMilliseconds;
            Console.WriteLine("[Normal] Process time : " + sw1time  + " ms.");
 
            // ใช้ Append ของ StringBuilder
            Stopwatch sw2 = new Stopwatch();
            StringBuilder fooString2 = new StringBuilder();
            sw2.Start();
            for (int i = 0; i < 10000; i++)
            {
                fooString2.Append(i.ToString());
            }
            sw2.Stop();
            string sw2time = sw2.ElapsedMilliseconds;
            Console.WriteLine("[StringBuilder] Process time : " + sw2time  + " ms.");
            Console.ReadKey();
        }
    }
}