AddBusinessDays和GetBusinessDays
我需要找到2个完美的完整实现
public static DateTime AddBusinessDays(this DateTime date, int days)
{
// code here
}
and
public static int GetBusinessDays(this DateTime start, DateTime end)
{
// code here
}
O（1）更好（没有循环）。
编辑：工作日我的意思是工作日（星期一，星期二，星期三，星期四，星期五）。 没有假期，只是周末排除在外。
我已经有一些看起来可行的丑陋解决方案，但我想知道是否有优雅的方法来做到这一点。 谢谢
这是我迄今写的。 它在所有情况下都有效，并且也会产生负面影响。 仍然需要一个GetBusinessDays实现
public static DateTime AddBusinessDays(this DateTime startDate,
int businessDays)
{
int direction = Math.Sign(businessDays);
if(direction == 1)
{
if(startDate.DayOfWeek == DayOfWeek.Saturday)
{
startDate = startDate.AddDays(2);
businessDays = businessDays - 1;
}
else if(startDate.DayOfWeek == DayOfWeek.Sunday)
{
startDate = startDate.AddDays(1);
businessDays = businessDays - 1;
}
}
else
{
if(startDate.DayOfWeek == DayOfWeek.Saturday)
{
startDate = startDate.AddDays(-1);
businessDays = businessDays + 1;
}
else if(startDate.DayOfWeek == DayOfWeek.Sunday)
{
startDate = startDate.AddDays(-2);
businessDays = businessDays + 1;
}
}
int initialDayOfWeek = (int)startDate.DayOfWeek;
int weeksBase = Math.Abs(businessDays / 5);
int addDays = Math.Abs(businessDays % 5);
if((direction == 1 && addDays + initialDayOfWeek > 5) ||
(direction == -1 && addDays >= initialDayOfWeek))
{
addDays += 2;
}
int totalDays = (weeksBase * 7) + addDays;
return startDate.AddDays(totalDays * direction);
}
您的第一个功能的最新尝试：
public static DateTime AddBusinessDays(DateTime date, int days)
{
if (days < 0)
{
throw new ArgumentException("days cannot be negative", "days");
}
if (days == 0) return date;
if (date.DayOfWeek == DayOfWeek.Saturday)
{
date = date.AddDays(2);
days -= 1;
}
else if (date.DayOfWeek == DayOfWeek.Sunday)
{
date = date.AddDays(1);
days -= 1;
}
date = date.AddDays(days / 5 * 7);
int extraDays = days % 5;
if ((int)date.DayOfWeek + extraDays > 5)
{
extraDays += 2;
}
return date.AddDays(extraDays);
}
第二个函数GetBusinessDays可以实现如下：
public static int GetBusinessDays(DateTime start, DateTime end)
{
if (start.DayOfWeek == DayOfWeek.Saturday)
{
start = start.AddDays(2);
}
else if (start.DayOfWeek == DayOfWeek.Sunday)
{
start = start.AddDays(1);
}
if (end.DayOfWeek == DayOfWeek.Saturday)
{
end = end.AddDays(-1);
}
else if (end.DayOfWeek == DayOfWeek.Sunday)
{
end = end.AddDays(-2);
}
int diff = (int)end.Subtract(start).TotalDays;
int result = diff / 7 * 5 + diff % 7;
if (end.DayOfWeek < start.DayOfWeek)
{
return result - 2;
}
else{
return result;
}
}
使用Fluent DateTime：
var now = DateTime.Now;
var dateTime1 = now.AddBusinessDays(3);
var dateTime2 = now.SubtractBusinessDays(5);
内部代码如下
/// <summary>
/// Adds the given number of business days to the <see cref="DateTime"/>.
/// </summary>
/// <param name="current">The date to be changed.</param>
/// <param name="days">Number of business days to be added.</param>
/// <returns>A <see cref="DateTime"/> increased by a given number of business days.</returns>
public static DateTime AddBusinessDays(this DateTime current, int days)
{
var sign = Math.Sign(days);
var unsignedDays = Math.Abs(days);
for (var i = 0; i < unsignedDays; i++)
{
do
{
current = current.AddDays(sign);
}
while (current.DayOfWeek == DayOfWeek.Saturday ||
current.DayOfWeek == DayOfWeek.Sunday);
}
return current;
}
/// <summary>
/// Subtracts the given number of business days to the <see cref="DateTime"/>.
/// </summary>
/// <param name="current">The date to be changed.</param>
/// <param name="days">Number of business days to be subtracted.</param>
/// <returns>A <see cref="DateTime"/> increased by a given number of business days.</returns>
public static DateTime SubtractBusinessDays(this DateTime current, int days)
{
return AddBusinessDays(current, -days);
}
我创建了一个扩展，允许您添加或减少工作日。 使用负数的businessDays减去。 我认为这是相当优雅的解决方案。 它似乎适用于所有情况。
namespace Extensions.DateTime
{
public static class BusinessDays
{
public static System.DateTime AddBusinessDays(this System.DateTime source, int businessDays)
{
var dayOfWeek = businessDays < 0
? ((int)source.DayOfWeek - 12) % 7
: ((int)source.DayOfWeek + 6) % 7;
switch (dayOfWeek)
{
case 6:
businessDays--;
break;
case -6:
businessDays++;
break;
}
return source.AddDays(businessDays + ((businessDays + dayOfWeek) / 5) * 2);
}
}
}
例：
using System;
using System.Windows.Forms;
using Extensions.DateTime;
namespace AddBusinessDaysTest
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
label1.Text = DateTime.Now.AddBusinessDays(5).ToString();
label2.Text = DateTime.Now.AddBusinessDays(-36).ToString();
}
}
}