使用C＃中的DateTime计算事件的复发 [英] Calculating recurrence of events using DateTime in C#

问题描述

我有一系列重复发生的事件。我需要能够计算这些事件何时发生在接下来的5周左右。

此系统将通知用户本月内将发生这些事件。

例如：

Event1

• = 2011年12月19日星期一


• 复发模式 =星期一/四周

Event2

• 开始日期 = 2012年2月3日


• 复发模式 =周三/每三周

3月22日 - 在接下来的5周内，活动1&

如果能够检测是否是圣诞节，那么事件将会落到另一天，这也是有用的。

我正在使用.NET MVC2，但我猜是这是偶然的。

感谢任何帮助

解决方案

这样的事情应该是诀窍：

  //枚举各种模式
 public enum OccurrenceRate 
 {
每周，
每周两次，
每月
} 
 
 public static List&Date日期& GetOccurrences（DateTime startDate，DateTime endDate，OccurrenceRate rate）
 {
列表< DateTime>出现=新List< DateTime>（）; 
 
 var nextDate = startDate; 
 
 while（true）
 {
 if（nextDate< = endDate）
 {
 occurrences.Add（nextDate）; 
} 
 else 
 {
 break; 
} 
 
 switch（rate）
 {
 case OccurrenceRate.Weekly：
 {
 nextDate = nextDate.AddDays（7）; 
 break; 
} 
 case OccurrenceRate.Fortnightly：
 {
 nextDate = nextDate.AddDays（14）; 
 break; 
} 
 case OccurrenceRate.Monthly：
 {
 nextDate = nextDate.AddMonths（1）; 
 break; 
} 
} 
} 
 
返回事件; 
} 
  

调用代码示例：

  DateTime startDate = DateTime.Now; 
 DateTime endDate = startDate.AddDays（35）; // 5周
 
 var dates = GetOccurrences（startDate，startDate.AddDays（35），OccurrenceRate.Weekly）; 
 dates.ForEach（date => 
 {
 Console.WriteLine（{0：yyyy-MM-dd}，date）; 
}）; 
  

I have a set of events that reoccur. I need to be able to calculate when these events occur with the next 5 weeks or so.

This system will inform the user that within this month, these events will occur..

For example:

Event1

• Date Started = Monday 19th Dec 2011
• Recurrence Pattern = Monday/Fortnightly

Event2

• Date Started = Thursday 3rd Feb 2012
• Recurrence Pattern = Thursday/Every Three Weeks

It's now 22 March - within the next 5 weeks what dates will Events 1 & 2 fall on.

It would also be useful to be able to detect if it's Xmas then the event will fall onto another day.

I'm using .NET MVC2 but I guess that's incidental.

Thanks for any assistance

解决方案

Something like this should do the trick:

//enum for various patterns
public enum OccurrenceRate
{
    Weekly,
    Fortnightly,
    Monthly
}

public static List<DateTime> GetOccurrences(DateTime startDate, DateTime endDate, OccurrenceRate rate)
{
    List<DateTime> occurrences = new List<DateTime>();

    var nextDate = startDate;

    while (true)
    {
        if (nextDate <= endDate)
        {
            occurrences.Add(nextDate);
        }
        else
        {
            break;
        }

        switch (rate)
        {
            case OccurrenceRate.Weekly:
            {
                nextDate = nextDate.AddDays(7);
                break;
            }
            case OccurrenceRate.Fortnightly:
            {
                nextDate = nextDate.AddDays(14);
                break;
            }
            case OccurrenceRate.Monthly:
            {
                nextDate = nextDate.AddMonths(1);
                break;
            }
        }
    }

    return occurrences;
}

Example of calling code:

DateTime startDate = DateTime.Now;
DateTime endDate = startDate.AddDays(35); //5 weeks

var dates = GetOccurrences(startDate, startDate.AddDays(35), OccurrenceRate.Weekly);
dates.ForEach(date =>
{
    Console.WriteLine("{0:yyyy-MM-dd}", date);
});

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