StopWatch 在 using System.Diagnostics 命名空間，需先引用。

using System;
using System.Diagnostics;

namespace StopWatch計時
{
    static class Program
    {
        static void Main()
        {
            //▼ 創(chuàng)建一個Stopwatch實例
            Stopwatch stopWatch = new Stopwatch();
            stopWatch.Start(); //開始計時

            for (int i = 0; i < 200; i++) {
                Console.Write(i + " ");
            }
            Console.WriteLine();

            stopWatch.Stop();  //停止計時

            Console.WriteLine("耗時：" + stopWatch.ElapsedMilliseconds + " ms  ");
            stopWatch.Reset();   //重置StopWatch
            Console.WriteLine("耗時：" + stopWatch.ElapsedMilliseconds + " ms  ");
            stopWatch.Restart();  //重新啟動被停止的StopWatch
            for (int i = 0; i < 100; i++) {
                Console.Write(i + " ");
            }
            Console.WriteLine();
            stopWatch.Stop();
            // ▼ 獲取stopWatch從開始到現(xiàn)在的時間差，單位是毫秒 -> stopWatch.ElapsedMilliseconds
            Console.WriteLine("耗時：" + stopWatch.ElapsedMilliseconds + " ms  ");
        }
    }
}

輸出：

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56
 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 8
3 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 10
7 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 12
7 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 14
7 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 16
7 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 18
7 188 189 190 191 192 193 194 195 196 197 198 199
耗時：11 ms
耗時：0 ms
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56
 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 8
3 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
耗時：3 ms
請按任意鍵繼續(xù). . .