C# : 測試程式執行的時間 (Time measurement)

using System.Diagnostics; // Stopwatch
using System.Threading; // Thread.Sleep

static void Main(string[] args)
{
    Stopwatch stopWatch = new Stopwatch();
    
    stopWatch.Start();
    Thread.Sleep(1000);
    stopWatch.Stop();

    // Get the elapsed time as a TimeSpan value.
    TimeSpan ts = stopWatch.Elapsed;

    // Format and display the TimeSpan value.
    string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:000}",
        ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds);

    Console.WriteLine("RunTime " + elapsedTime);
    Console.ReadLine();
}

Reference:
https://msdn.microsoft.com/zh-tw/library/system.diagnostics.stopwatch(v=vs.110).aspx