c# 获取 本周、本月、本季度、本年 的开始时间或结束时间

#region 获取 本周、本月、本季度、本年 的开始时间或结束时间
/// <summary>
/// 获取结束时间
/// </summary>
/// <param name="TimeType">Week、Month、Season、Year</param>
/// <param name="now"></param>
/// <returns></returns>
public static DateTime? GetTimeStartByType(string TimeType, DateTime now)
{
switch (TimeType)
{
case "Week":
return now.AddDays(-(int)now.DayOfWeek + 1);
case "Month":
return now.AddDays(-now.Day + 1);
case "Season":
var time = now.AddMonths(0 - ((now.Month - 1) % 3));
return time.AddDays(-time.Day + 1);
case "Year":
return now.AddDays(-now.DayOfYear + 1);
default:
return null;
}
}

/// <summary>
/// 获取结束时间
/// </summary>
/// <param name="TimeType">Week、Month、Season、Year</param>
/// <param name="now"></param>
/// <returns></returns>
public static DateTime? GetTimeEndByType(string TimeType, DateTime now)
{
switch (TimeType)
{
case "Week":
return now.AddDays(7 - (int)now.DayOfWeek);
case "Month":
return now.AddMonths(1).AddDays(-now.AddMonths(1).Day + 1).AddDays(-1);
case "Season":
var time = now.AddMonths((3 - ((now.Month - 1) % 3) - 1));
return time.AddMonths(1).AddDays(-time.AddMonths(1).Day + 1).AddDays(-1);
case "Year":
var time2 = now.AddYears(1);
return time2.AddDays(-time2.DayOfYear);
default :
return null;
}
}
#endregion