/// <summary>
/// Gets first day of year
/// </summary>
/// <param name="dt"></param>
/// <param name="dayOfWeek"></param>
/// <returns></returns>
public static DateInfo GetFirstDayInfoOfYear(this DateTime dt, DayOfWeek dayOfWeek)
{
var t = DateTimeFactory.Create(dt.Year, 1, 1);
while (t.DayOfWeek != dayOfWeek)
{
t = t.AddDays(-1);
}
return(t);
}
public static int GetTargetDays(int year, int month, int weekAtMonth, int dayOfWeek)
{
var fd = DateTimeFactory.Create(year, month, 1);
var daysNeeded = dayOfWeek - (int)fd.DayOfWeek;
if (daysNeeded < 0)
{
daysNeeded += 7;
}
return((daysNeeded + 1) + (7 * (weekAtMonth - 1)));
}
/// <summary>
/// Previous Year
/// </summary>
/// <param name="dt"></param>
/// <returns></returns>
public static DateTime PreviousYear(this DateTime dt)
{
var year = dt.Year - 1;
var daysOfMonth = DateTime.DaysInMonth(year, dt.Month);
if (daysOfMonth == dt.Day)
{
return(DateTimeFactory.Create(year, dt.Month, dt.Day, dt.Hour, dt.Minute, dt.Second, dt.Millisecond, dt.Kind));
}
var d = dt.Day - daysOfMonth;
var p = DateTimeFactory.Create(year, dt.Month, daysOfMonth, dt.Hour, dt.Minute, dt.Second, dt.Millisecond, dt.Kind);
return(p + d.Days());
}
/// <summary>
/// Create <see cref="DateTime"/> by special year, month and offset info.<br />
/// 根据指定的年月和偏移信息创建 <see cref="DateTime"/>
/// </summary>
/// <param name="year"></param>
/// <param name="month"></param>
/// <param name="weekAtMonth"></param>
/// <param name="dayOfWeek"></param>
/// <returns></returns>
public static DateTime OffsetByWeek(int year, int month, int weekAtMonth, int dayOfWeek)
{
if (weekAtMonth == 0 || weekAtMonth > 5)
{
throw new ArgumentException("weekAtMonth is invalid.", nameof(weekAtMonth));
}
var targetDay = DateTimeCalcHelper.GetTargetDays(year, month, weekAtMonth, dayOfWeek);
if (targetDay > DateTime.DaysInMonth(year, month))
{
return(DateTime.MinValue);
}
return(DateTimeFactory.Create(year, month, targetDay));
}
/// <summary>
/// Create <see cref="DateInfo"/> by special year, month and offset info.<br />
/// 根据指定的年月和偏移信息创建 <see cref="DateInfo"/>
/// </summary>
/// <param name="year"></param>
/// <param name="month"></param>
/// <param name="weekAtMonth"></param>
/// <param name="dayOfWeek"></param>
/// <param name="result"></param>
/// <returns></returns>
public static bool TryOffsetByWeek(int year, int month, int weekAtMonth, int dayOfWeek, out DateInfo result)
{
if (weekAtMonth == 0 || weekAtMonth > 5)
{
throw new ArgumentException("weekAtMonth is invalid.", nameof(weekAtMonth));
}
var targetDay = DateTimeCalcHelper.GetTargetDays(year, month, weekAtMonth, dayOfWeek);
var invalid = targetDay > DateTime.DaysInMonth(year, month);
result = invalid
? DateTime.MinValue
: DateTimeFactory.Create(year, month, targetDay);
return(!invalid);
}
/// <summary> /// Set time /// </summary> /// <param name="dt"></param> /// <param name="millisecond"></param> /// <returns></returns> public static DateTime SetMillisecond(this DateTime dt, int millisecond) => DateTimeFactory.Create(dt.Year, dt.Month, dt.Day, dt.Hour, dt.Minute, dt.Second, millisecond, dt.Kind);
/// <summary> /// Set time /// </summary> /// <param name="dt"></param> /// <param name="hour"></param> /// <param name="minute"></param> /// <param name="second"></param> /// <param name="millisecond"></param> /// <returns></returns> public static DateTime SetTime(this DateTime dt, int hour, int minute, int second, int millisecond) => DateTimeFactory.Create(dt.Year, dt.Month, dt.Day, hour, minute, second, millisecond, dt.Kind);
/// <summary> /// Set date /// </summary> /// <param name="dt"></param> /// <param name="year"></param> /// <returns></returns> public static DateTime SetYear(this DateTime dt, int year) => DateTimeFactory.Create(year, dt.Month, dt.Day, dt.Hour, dt.Minute, dt.Second, dt.Millisecond, dt.Kind);
/// <summary> /// Set date /// </summary> /// <param name="dt"></param> /// <param name="year"></param> /// <param name="month"></param> /// <param name="day"></param> /// <returns></returns> public static DateTime SetDate(this DateTime dt, int year, int month, int day) => DateTimeFactory.Create(year, month, day, dt.Hour, dt.Minute, dt.Second, dt.Millisecond, dt.Kind);
/// <summary> /// End of day (timezone-adjusted) /// </summary> /// <param name="dt"></param> /// <param name="timeZoneOffset"></param> /// <returns></returns> public static DateTime EndOfDay(this DateTime dt, int timeZoneOffset) => DateTimeFactory.Create(dt.Year, dt.Month, dt.Day, 23, 59, 59, 999, dt.Kind).AddHours(timeZoneOffset);
/// <summary> /// End of day /// </summary> /// <param name="dt"></param> /// <returns></returns> public static DateTime EndOfDay(this DateTime dt) => DateTimeFactory.Create(dt.Year, dt.Month, dt.Day, 23, 59, 59, 999, dt.Kind);
/// <summary> /// To Datetime /// </summary> /// <param name="lt"></param> /// <param name="day"></param> /// <param name="kind"></param> /// <param name="year"></param> /// <param name="month"></param> /// <returns></returns> public static DateTime ToDateTime(this LocalTime lt, int year, int month, int day, DateTimeKind kind) => DateTimeFactory.Create(year, month, day, lt.Hour, lt.Minute, lt.Second, lt.Millisecond, kind);
/// <summary> /// Beginning of day /// </summary> /// <param name="dt"></param> /// <param name="timeZoneOffset"></param> /// <returns></returns> public static DateTime BeginningOfDay(this DateTime dt, int timeZoneOffset) => DateTimeFactory.Create(dt.Year, dt.Month, dt.Day, 0, 0, 0, 0, dt.Kind).AddHours(timeZoneOffset);
/// <summary> /// Beginning of day /// </summary> /// <param name="dt"></param> /// <returns></returns> public static DateTime BeginningOfDay(this DateTime dt) => DateTimeFactory.Create(dt.Year, dt.Month, dt.Day, 0, 0, 0, 0, dt.Kind);
/// <summary> /// Convert <see cref="DateTime"/> to Epoch time span. /// </summary> /// <param name="dt"></param> /// <returns></returns> public static TimeSpan ToEpochTimeSpan(this DateTime dt) => dt.Subtract(DateTimeFactory.Create(1970, 1, 1));
/// <summary> /// To Datetime /// </summary> /// <param name="ld"></param> /// <param name="kind"></param> /// <returns></returns> public static DateTime ToDateTime(this LocalDate ld, DateTimeKind kind) => DateTimeFactory.Create(ld.Year, ld.Month, ld.Day, 0, 0, 0, 0, kind);
