原理其實非常簡單，取出兩個時間差的秒數，再在0到該秒數之間隨機獲取一個整數，將其做為秒添加到較小的時間上，可以說實現上并沒什么技術難點，可以在數據類型的邊界條件上卻需要格外的注意，比如將大于 system.int32.maxvalue 或小于 system.int32.minvalue 的值轉成 int 時，如果直接在變量前加上類型名轉換（(int)d），不會有有異常產生，但得到的值卻是 system.int32.minvalue，還有就是對于math.abs 方法，當參數 value 等于 minvalue 將會引發 system.overflowexception 異常。

代碼如下：

using system;

namespace yyw
{
    public class datetimehelper
    {
        /**//// <summary>
        /// 獲取隨機時間
        /// <remarks>
        /// 由于random 以當前系統時間做為種值,所以當快速運行多次該方法所得到的結果可能相同,
        /// 這時,你應該在外部初始化 random 實例并調用 getrandomtime(datetime time1, datetime time2, random random)
        /// </remarks>
        /// </summary>
        /// <param name="time1"></param>
        /// <param name="time2"></param>
        /// <returns></returns>
        public static datetime getrandomtime(datetime time1, datetime time2)
        {
            random random = new random();
            return getrandomtime(time1, time2, random);
        }

        /**//// <summary>
        /// 獲取隨機時間
        /// </summary>
        /// <param name="time1"></param>
        /// <param name="time2"></param>
        /// <param name="random"></param>
        /// <returns></returns>
        public static datetime getrandomtime(datetime time1, datetime time2, random random)
        {
            datetime mintime = new datetime();
            datetime maxtime = new datetime();

            system.timespan ts = new system.timespan(time1.ticks - time2.ticks);

            // 獲取兩個時間相隔的秒數
            double dtotalsecontds = ts.totalseconds;
            int itotalsecontds = 0;

            if (dtotalsecontds > system.int32.maxvalue)
            {
                itotalsecontds = system.int32.maxvalue;
            }
            else if (dtotalsecontds < system.int32.minvalue)
            {
                itotalsecontds = system.int32.minvalue;
            }
            else
            {
                itotalsecontds = (int)dtotalsecontds;
            }

            if (itotalsecontds > 0)
            {
                mintime = time2;
                maxtime = time1;
            }
            else if (itotalsecontds < 0)
            {
                mintime = time1;
                maxtime = time2;
            }
            else
            {
                return time1;
            }

            int maxvalue = itotalsecontds;

            if (itotalsecontds <= system.int32.minvalue)
                maxvalue = system.int32.minvalue + 1;

            int i = random.next(system.math.abs(maxvalue));

            return mintime.addseconds(i);
        }
    }
}
測試代碼：

using system;
using nunit.framework;

namespace yyw
{
    [testfixture]
    public class datetimehelperfixture
    {
        /**//// <summary>
        /// 邊界測試
        /// </summary>
        [test]
        public void testgetrandomtime()
        {
            datetime mintime = datetime.minvalue;
            datetime maxtime = datetime.maxvalue;
            random random = new random();

            for (int i = 0; i < 10000; i++)
            {
                datetime randomtime = datetimehelper.getrandomtime(maxtime, mintime, random);
                checkresult(mintime, maxtime, randomtime);
            }

            for (int i = 0; i < 10000; i++)
            {
                datetime randomtime = datetimehelper.getrandomtime(mintime, maxtime, random);
                checkresult(mintime, maxtime, randomtime);
            }
        }

        private void checkresult(datetime mintime, datetime maxtime, datetime randomtime)
        {
            system.timespan ts1 = new system.timespan(randomtime.ticks - mintime.ticks);
            system.timespan ts2 = new system.timespan(randomtime.ticks - maxtime.ticks);
            assert.istrue(ts1.seconds >= 0 && ts2.seconds <= 0);
        }
    }
}