从1970年1月1日00:00:00 GMT以来此时间对象表示的毫秒数转化为Datetime

/// <summary>
/// 将Long类型转换为DateTime类型
/// </summary>
/// <param name="d">long</param>
/// <returns></returns>
public static DateTime ConvertLongDateTime(long ticks)
{
DateTime dtBase = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
DateTime convertTime = dtBase.Add(new TimeSpan(ticks * TimeSpan.TicksPerMillisecond)).ToLocalTime();
return convertTime;
}

/// <summary>
/// 将DateTime类型转换为long类型
/// </summary>
/// <param name="dt">时间</param>
/// <returns></returns>
public static long ConvertDataTimeLong(DateTime dt)
{
DateTime dtBase = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
TimeSpan toNow = DateTime.Now.Subtract(dtBase);
long timeStamp = toNow.Ticks;
return timeStamp;
}