检查日期范围是一个日期范围内 [英] Check if a date range is within a date range

问题描述

我有以下类：

public class Membership
{
    public DateTime StartDate { get; set; }
    public DateTime? EndDate { get; set; } // If null then it lasts forever
}

我需要确保当添加下面的列表，新项目不重叠，从现有项目的日期：

I need to make sure when adding to the following list that the new item doesn't overlap the dates from existing item:

var membership = new List<Membership>
{
    new Membership { StartDate = DateTime.UtcNow.AddDays(-10), EndDate = DateTime.UtcNow.AddDays(-5) },
    new Membership { StartDate = DateTime.UtcNow.AddDays(-5), EndDate = null }
};

例如这样做的：

var newItem = new Membership { StartDate = DateTime.UtcNow.AddDays(-15), EndDate = DateTime.UtcNow.AddDays(-10) }; // Allowed

var newItem2 = new Membership { StartDate = DateTime.UtcNow.AddDays(-15), EndDate = null }; // Not Allowed

if (AllowededToAdd(newItem))
    membership.Add(newItem);

if (AllowededToAdd(newItem2))
    membership.Add(newItem2);

我想这将是简单的，但到目前为止，我尝试都错了，我开始迷惑自己，希望有人做了类似的事情，他们可以分享。感谢

I thought this would be simple but so far my attempts have all been wrong and i'm starting to confuse myself and was hoping someone had done something similar they could share. Thanks

推荐答案

基本上，一个时间范围重叠另一个如果任何其结局是其他范围内，或反之亦然。

Basically, a date range overlaps another if any of its endings are within the other range, or vice versa.

static bool AllowedToAdd(List<Membership> membershipList, Membership newItem)
{
    return !membershipList.Any(m =>
        (m.StartDate < newItem.StartDate &&
         newItem.StartDate < (m.EndDate ?? DateTime.MaxValue))
        ||
        (m.StartDate < (newItem.EndDate ?? DateTime.MaxValue) &&
         (newItem.EndDate ?? DateTime.MaxValue) <= (m.EndDate ?? DateTime.MaxValue))
        ||
        (newItem.StartDate < m.StartDate &&
         m.StartDate < (newItem.EndDate ?? DateTime.MaxValue))
        ||
        (newItem.StartDate < (m.EndDate ?? DateTime.MaxValue) &&
         (m.EndDate ?? DateTime.MaxValue) <= (newItem.EndDate ?? DateTime.MaxValue))
        );
}

通过使用：

if (AllowedToAdd(membershipList, newItem))
    membershipList.Add(newItem);

这篇关于检查日期范围是一个日期范围内的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！