2

我需要返回按时间顺序排列的警报列表。下面的方法 1 就是这样做的。

我还需要获取某种警报类型的警报，如果 AlertTypeID = {1,2,3,6,8,9,x}，则按 CreateDate 返回这些警报并按月排序。下面的方法 2 就是这样做的。

现在，我需要将方法 2 的结果插入到方法 1 的结果中。尽管方法 2 返回的项目是按月份组织的，但我们只关心最近的。只有方法 2 中最近的子组项目需要遵循方法 1 返回的项目的时间顺序。该子组项目将确定子组 2 中其余每月项目的放置位置。

最后一个要求是必须删除重复项。如果从子组警报返回的项目，则它不能也存在于主要组警报中。

下面我提供了一个我想要达到的效果的说明：

december alert 1 (12/23/2012)
december alert 2 (12/21/2012)
december alert 3 (12/20/2012)
december subalert 1 (12/19/2012)
december subalert 2 (12/18/2012)
december subalert 3 (12/04/2012)
december subalert 4 (12/01/2012)
december alert 4 (12/18/2012)
december alert 5 (12/12/2012)
november alert 1 (11/22/2012)
november alert 2 (11/16/2012)
november subalert 1 (11/14/2012)
november subalert 2 (11/08/2012)
november alert 3 (11/12/2012)

代码：

  1. 日期时间的所有警报

    List<Alert> result = new List<Alert>();
using(NeuroLabLinqDataContext dc = conn.GetContext())
{
    IEnumerable<Alert> alerts = (from a in dc.Alerts
                                 where a.AccountID == AccountID
                                 orderby a.CreateDate descending
                                 select a).Take(40);
    result = alerts.ToList();
}
return result;

  2. 按月划分的警报类型

    List<Alert> result = new List<Alert>();
int[] alertTypes = {1,2,3,4,5,6,7,8,9};

using (NeuroLabLinqDataContext dc = conn.GetContext())
{
    IEnumerable<Alert> alerts = (from a in dc.Alerts
                                 where a.AccountID == AccountID &&
                                 alertTypes.Contains(a.AlertTypeID)
                                 orderby ((DateTime)a.CreateDate).Month ascending
                                 select a).ToList();
}

return result;

最终 select 语句的分组应如下所示：

 select new { Date = alerts.CreateDate, 
              Message = alerts.Message, 
              Type = alert.AlertTypeID, 
              RecentActivity = [if from method 2, then true] };

更新：更新方法

 public List<Alert> GetAlertsByAccountID(Int32 AccountID, params int[] alertTypes)
        {

            List<Alert> result = new List<Alert>();

            using (NeuroLabLinqDataContext dc = conn.GetContext())
            {
                var all = (from a in dc.Alerts
                           where a.AccountID == AccountID
                           orderby a.CreateDate descending
                           select a);

                int abc = all.Count();

                var first = all
                    .Where(a => a.AccountID == AccountID) && !alertTypes.Contains(a.AlertTypeID))
                    .OrderByDescending(a => a.CreateDate)
                    .GroupBy(a => a.CreateDate.Date)
                    .ToDictionary(g => g.Key);

                var firstKeys = first.Keys.Cast<DateTime>()
                    .ToList().OrderBy(k => k);

                var second = all
                    .Where(a => a.AccountID == AccountID) && alertTypes.Contains(a.AlertTypeID))
                    .OrderBy(a => a.CreateDate.Month)
                    .GroupBy(a => a.CreateDate.Month)
                    .ToDictionary(g => firstKeys
                        .First(k => k > g.OrderByDescending(a => a.CreateDate)
                        .FirstOrDefault().CreateDate));

                var combined = first
                    .GroupJoin(
                        second,
                        fk => fk.Key,
                        sk => sk.Key,
                        (d, l) => d.Value
                            .Union(l.SelectMany(i => i.Value).ToArray()))
                    .SelectMany(i => i);

                    result = combined.ToList(); 
            }

            return result;

        }

多亏了约翰，我走得更远了。目前，我收到以下错误：

序列不包含匹配元素

在这一行（我很确定）：

.First(k => k > g.OrderByDescending(a => a.CreateDate)

对于它的价值，这是我的警报表中的数据的样子。

AlertID AccountID   CreateDate  Timestamp   AlertTypeID    Message
122 5   2008-03-11 20:48:07.983 0x00000000000128FB  9        sdfs
123 1   2008-03-11 20:48:39.957 0x00000000000128FE  8        sdfsd
124 5   2008-03-11 20:48:39.977 0x00000000000128FF  8        sdfs
125 5   2008-03-11 20:48:40.017 0x0000000000012901  8        asdfa
126 1   2008-03-12 22:57:42.160 0x00000000000130B3  4        sfsf
127 5   2008-03-12 22:57:42.337 0x00000000000130B4  4        sdfsd
128 5   2008-03-13 09:42:14.237 0x0000000000013889  4        sdfsd
129 5   2008-03-13 09:42:31.957 0x000000000001388B  4        sdfsd
130 5   2008-03-13 09:42:45.397 0x000000000001388D  5        asdfsdf
131 1   2008-03-16 14:52:17.197 0x0000000000014822  9        asdfsdf
132 1   2008-04-12 15:25:17.330 0x000000000001B582  3        sfasdf
133 5   2008-04-12 15:25:17.700 0x000000000001B583  3        dfsfds
134 6   2008-04-14 08:37:03.273 0x000000000001BD87  3        aasfsd
135 6   2008-04-14 08:37:15.270 0x000000000001BD89  3        fhfsdf
136 6   2008-04-14 08:38:45.120 0x000000000001BD8B  2        ghsdgd
137 6   2008-04-14 08:41:30.407 0x000000000001BD9A  4        fghsdfg
138 6   2008-04-14 08:42:30.800 0x000000000001BD9C  4        gfsdf
139 6   2008-04-14 08:42:43.763 0x000000000001BD9E  5        sdfsdf
140 6   2008-04-14 08:49:25.450 0x000000000001BDAA  9        sdfasdfa
141 6   2008-04-14 08:49:34.237 0x000000000001BDAC  9        sdfasdf
142 1   2008-04-14 08:50:23.380 0x000000000001BDAF  8        sdfhdfhsg
143 6   2008-04-14 08:50:23.567 0x000000000001BDB0  8        dgasdf
144 5   2008-04-14 08:50:23.690 0x000000000001BDB1  8        dgasdf
145 6   2008-04-14 08:50:23.747 0x000000000001BDB2  8         dgasdf
147 1   2008-06-24 14:22:41.183 0x00000000000222E6  14       dgasdf
148 5   2008-06-24 14:22:41.617 0x00000000000222E7  14       dgasdf
149 6   2008-06-24 14:22:41.623 0x00000000000222E8  14       dgasdf
150 1   2008-06-24 20:11:57.757 0x0000000000022AB3  13     dgasdf
151 5   2008-06-24 20:11:57.947 0x0000000000022AB4  13       dgasdf
152 6   2008-06-24 20:11:57.953 0x0000000000022AB5  13       dgasdf
153 1   2008-07-03 18:41:51.067 0x0000000000028888  14       dgasdf
154 5   2008-07-03 18:41:51.230 0x0000000000028889  14        dgasdf
155 6   2008-07-03 18:41:51.237 0x000000000002888A  14        dgasdf
156 1   2008-07-03 18:46:17.873 0x000000000002888D  14       dgasdf
157 5   2008-07-03 18:46:17.937 0x000000000002888E  14       dgasdf
158 6   2008-07-03 18:46:17.940 0x000000000002888F  14        dgasdf
4

1 回答 1

3

关键是将两组分解成字典，使用第一个列表中的日期作为字典的键，并选择第二个列表项日期之后最接近的键作为第二个字典的键。

一旦你有了两个字典，每个字典都使用类型和子类型的公共键值，你可以做 aGroupJoin并SelectMany在排序列表中获取结果。

（*请注意，答案是基于一个稍微不同的早期版本的问题，我不会花时间更新答案，因为我认为基本问题已经在这个答案中得到说明和解决）

更新 2 我意识到您在 First() 调用中看到的问题是您的某些子警报项可能比任何其他会导致您的异常的警报项更新。我通过使用 向第一个字典添加一个“代理”键来解决这个问题DateTime::MaxValue，然后我不再从第一个列表中过滤掉子警报，我只是.Distinct()在最终结果上使用来删除重复项

使用 linqpad 我模拟了这个问题并使用字典解决了它GroupJoin

var all = new []{
    new {date = DateTime.Parse("2012-12-23"), type = "alert", value = 1, accountId = 333 },
    new {date = DateTime.Parse("2012-12-21"), type = "alert", value = 2, accountId = 333 },
    new {date = DateTime.Parse("2012-12-20"), type = "alert", value = 3, accountId = 333 },
    new {date = DateTime.Parse("2012-12-18"), type = "alert", value = 4, accountId = 333 },
    new {date = DateTime.Parse("2012-12-12"), type = "alert", value = 5, accountId = 333 },
    new {date = DateTime.Parse("2012-11-22"), type = "alert", value = 1, accountId = 333 },
    new {date = DateTime.Parse("2012-11-16"), type = "alert", value = 2, accountId = 333 },
    new {date = DateTime.Parse("2012-11-12"), type = "alert", value = 3, accountId = 333 },
    new {date = DateTime.Parse("2012-12-19"), type = "subalert", value = 1, accountId = 333 },
    new {date = DateTime.Parse("2012-12-18"), type = "subalert", value = 2, accountId = 333 },
    new {date = DateTime.Parse("2012-12-04"), type = "subalert", value = 3, accountId = 333 },
    new {date = DateTime.Parse("2012-12-01"), type = "subalert", value = 4, accountId = 333 },
    new {date = DateTime.Parse("2012-11-14"), type = "subalert", value = 1, accountId = 333 },
    new {date = DateTime.Parse("2012-11-08"), type = "subalert", value = 2, accountId = 333 },  
/*add*/ new {date = DateTime.Parse("2012-12-25"), type = "subalert", value = 9, accountId = 333 },  
};

var first = all
    .Where(a=>a.accountId == 333 /* removed && type != "alert" */)
    .OrderByDescending(a=>a.date)
    .GroupBy(a=>a.date.Date)
    .ToDictionary(g=>g.Key);

var firstKeys = first.Keys
    .Cast<DateTime>()
    .Union(new []{DateTime.MaxValue}) /* added this 'surrogate' key */
    .OrderBy(k=>k)
    .ToArray();

var second = all
    .Where(a=>a.accountId == 333 && a.type == "subalert")
    .OrderBy(a=>a.date.Month)
    .GroupBy(a=>a.date.Month)
    .ToDictionary(g=>firstKeys.First(k=>k > g.OrderByDescending(a=>a.date).FirstOrDefault().date));


var combined = first
    .GroupJoin(
        second,
        fk=>fk.Key,
        sk=>sk.Key,
        (d,l)=>d.Value
            .Union(l.SelectMany(i=>i.Value).ToArray()))
    .SelectMany(i=>i)
    .Distinct(); /* Added this to remove duplicates */

combined.Dump();

产生：

更新结果

于 2012-05-23T20:28:46.600 回答