/// <summary>
/// 年龄
/// </summary>
/// <param name="dt"></param>
/// <returns></returns>
public static int Age(this DateTime?dt)
{
return(SystemHelper.Age(dt, DateTime.Now));
}
/// <summary>
/// 格式化日期 yyyy-MM-dd
/// </summary>
/// <param name="dt"></param>
/// <returns></returns>
public static string Format(this DateTime dt)
{
return(SystemHelper.Format(dt, "yyyy-MM-dd"));
}