C# DateTime与时间戳970-01-01 00:00:00:00 起的毫秒数转换

 public static DateTime ConvertTimestampToDateTime(long timestamp)
    {
        DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
        DateTime utcDateTime = unixStart.AddMilliseconds(timestamp);
        return utcDateTime.ToLocalTime(); // 如果需要转换为本地时间，调用ToLocalTime()
    }
 
    public static long GetMillisecondsSinceUnixEpoch(DateTime dateTime)
    {
        DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
        TimeSpan timeSpan = dateTime.ToUniversalTime() - unixStart;
        return (long)timeSpan.TotalMilliseconds;
    }