如何使用 OData 和 LINQ 进行嵌套计数？

发布于 2024-09-13 06:24:14 字数 577 浏览 16 评论 0原文

这是我尝试从 OData 源运行的查询：

var query = from j in _auditService.AuditJobs.IncludeTotalCount()
   orderby j.Description
   select new 
      {
         JobId = j.ID,
         Description = j.Description,
         SubscriberCount = j.JobRuns.Count()
      };

如果我不使用 j.JobRuns.Count()，它运行得很好，但如果我包含它，我会收到以下错误：

构造或初始化实例类型的 <>f__AnonymousType1`3[System.Int32,System.String,System.Int32] 使用表达式 j.JobRuns.Count() 不支持。

尝试通过OData获取嵌套计数似乎是一个问题。有什么解决办法吗？我试图避免仅仅为了获得计数而获取每个对象的整个嵌套集合。

谢谢！

原文

Here is the query I am trying to run from my OData source:

var query = from j in _auditService.AuditJobs.IncludeTotalCount()
   orderby j.Description
   select new 
      {
         JobId = j.ID,
         Description = j.Description,
         SubscriberCount = j.JobRuns.Count()
      };

It runs great if I don't use the j.JobRuns.Count(), but if I include it I get the following error:

Constructing or initializing instances
of the type
<>f__AnonymousType1`3[System.Int32,System.String,System.Int32]
with the expression j.JobRuns.Count()
is not supported.

It seems to be a problem of attempting to get the nested count through OData. What is a work around for this? I was trying to avoid getting the whole nested collection for each object just to get a count.

Thanks!

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悲凉≈ 2024-09-20 06:24:14

截至目前，OData 协议不支持聚合。

预测是的，但包含聚合属性的预测则不是。

亚历克斯

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一束光，穿透我孤独的魂 2024-09-20 06:24:14

您需要 .Net 4.0 并且在 LinqPad 中您可以通过 netflix OData 服务运行以下命令

void Main()
{
    ShowPeopleWithAwards();
    ShowTitles();
}

// Define other methods and classes here
public void ShowPeopleWithAwards()
{
    var people = from p in People.Expand("Awards").AsEnumerable()
            where p.Awards.Count > 0
            orderby p.Name
            select new
            {
              p.Id,
                    p.Name,
              AwardCount = p.Awards.Count,
             TotalAwards = p.Awards.OrderBy (a => a.Type).Select (b => new { b.Type, b.Year} )
                 };

    people.Dump();
}

public void ShowTitles()
{
    var titles = from t in Titles.Expand("Awards").AsEnumerable()
            where t.ShortName != string.Empty && 
                  t.ShortSynopsis != string.Empty &&
             t.Awards.Count > 0
            select t;
    titles.Dump();
}

You need .Net 4.0 and In LinqPad you can run following over netflix OData Service

void Main()
{
    ShowPeopleWithAwards();
    ShowTitles();
}

// Define other methods and classes here
public void ShowPeopleWithAwards()
{
    var people = from p in People.Expand("Awards").AsEnumerable()
            where p.Awards.Count > 0
            orderby p.Name
            select new
            {
              p.Id,
                    p.Name,
              AwardCount = p.Awards.Count,
             TotalAwards = p.Awards.OrderBy (a => a.Type).Select (b => new { b.Type, b.Year} )
                 };

    people.Dump();
}

public void ShowTitles()
{
    var titles = from t in Titles.Expand("Awards").AsEnumerable()
            where t.ShortName != string.Empty && 
                  t.ShortSynopsis != string.Empty &&
             t.Awards.Count > 0
            select t;
    titles.Dump();
}

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