许多人使用linq进行可选的动态分组 [英] Optional dynamic grouping by many using linq

问题描述

我遇到动态分组问题。

我有一个要求，按钮可以拖动分组以生成报告



我尝试使用 dynamic linq 。我不想使用魔法字符串。



所以我决定花更多时间在不使用字符串的情况下获得一些东西。



我发现 C＃6.0 in a Nutshell - PredicateBuilder [ ^ ]和

其他扩展 c＃3.0 - 如何使用LINQ对数据进行分层分组？ - 堆栈溢出 [ ^ ]



但扩展中的GroupByMany具有委托作为函数而不表达。



所以我不能尝试像

< pre lang =   c＃>< pre lang =   c＃>< pre lang =   text >  

  foreach （ var 条目  resultEntries）
 {
  if （projectGroup ）
 predicate1 = predicate.And（p = >  p.Project.Id == e ntry.Project.Id）; 
 
  if （clientGroup）
 predicate2 = predicate.And（p = >  p.Client.Id == entry.Client.Id）; 
 
  if （userGroup）
 predicate3 = predicate.And（p = >  p.User.Id == entry.User.Id）; 
 
 predicateResult.And（predicate1）; 
 predicateResult.And（predicate2）; 
 predicateResult.And（predicate3）; 

}

 var output = resultEntries.GroupByMany（predicate） ; 

例如：一个场景的硬编码类型看起来像

  var  nestedGrouping = reportTimeEntries 
 .GroupByMany（t = >  t .Project.Id，t = >  t.Client.Id）; 

我希望这是因为我不知道过滤器被分组发送的顺序。



请帮助我。我在过去的三周内陷入困境。



我尝试过的事情：



公共enum eEntry

{

NotSet = 0，

[描述=客户]

客户= 1，

[ Description =Projects]

Projects = 2，

[Description =Users]

Users = 3

}





public void SubmitReport（EntryFilter filter）{//过滤器包含reportGroups和日期范围

var reportGroups =Projects，Clients ; //实际应该来自filter.But我显示一个场景

//注意：reportGroups可以是1.Clientslients，

// 2.Projects，< br $>
// 3.Users，

// 4.Clients，Projects，

// 5.Projects，Clients

// 6.客户，用户，

// 7.用户，客户，

// .....等所有可能的组合，包括可选< br $>


//以上用于GROUPING MY ENTRIES

List< entry> entries = services.getEntries（）;



//我想按报告组的ID进行分组

var projectGroup = reportGroups.Contains（eEntry .Projects）;

var clientGroup = reportGroups.Contains（eEntry.Clients）;

var userGroup = reportGroups.Contains（eEntry.Users）;



if（projectGroup）

entries.GroupBy（e => e.Project.Id）;



if（clientGroup）

entries.GroupBy（e => e.Client.Id）;



if（userGroup）

entries.GroupBy（e => e.User.Id）;

//和所有其他组合可能



}

解决方案

请，检查一下： Linq GroupByMany动态 - Mitsu的博客 [ ^ ]

Hi,
I am facing a problem with dynamic grouping.
I have a requirement where buttons are draggable for grouping for generating report

I tried using dynamic linq.I don't want to use magical string.

So I decided to take more time and get something without using strings.

I found C# 6.0 in a Nutshell - PredicateBuilder[^] and
other extension c# 3.0 - How can I hierarchically group data using LINQ? - Stack Overflow[^]

But GroupByMany in extension has delegate as function not expression.

So I could not try like

<pre lang="c#"><pre lang="c#"><pre lang="text">

foreach (var entry in resultEntries)
           {
               if (projectGroup)
                   predicate1 = predicate.And(p => p.Project.Id == entry.Project.Id);

               if (clientGroup)
                   predicate2 = predicate.And(p => p.Client.Id == entry.Client.Id);

               if (userGroup)
                   predicate3 = predicate.And(p => p.User.Id == entry.User.Id);

               predicateResult.And(predicate1);
               predicateResult.And(predicate2);
               predicateResult.And(predicate3);

}

var output  = resultEntries.GroupByMany(predicate);

Ex:Hardcoded type for one scenario looks like

var nestedGrouping = reportTimeEntries
                               .GroupByMany(t => t.Project.Id, t => t.Client.Id);

I want this to be dynamic.Because I don't know the order in which filter are sent for grouping.

Please help me.I am stuck from past three weeks.

What I have tried:

public enum eEntry
{
NotSet = 0,
[Description="Clients"]
Clients = 1,
[Description="Projects"]
Projects = 2,
[Description="Users"]
Users=3
}


public void SubmitReport(EntryFilter filter){//filter contain reportGroups and date range
var reportGroups="Projects,Clients";//actually should come from filter.But I am showing one scenario
//Note: reportGroups can be 1.Clientslients,
// 2.Projects,
// 3.Users,
// 4.Clients,Projects,
// 5.Projects,Clients
// 6.Clients,Users,
// 7.Users,Clients,
// ..... etc. with all possible combinations including optional

//Above are used for GROUPING MY ENTRIES
List<entry> entries=services.getEntries();

//I want to group by IDs of reportGroups
var projectGroup = reportGroups.Contains(eEntry.Projects);
var clientGroup = reportGroups.Contains(eEntry.Clients);
var userGroup = reportGroups.Contains(eEntry.Users);

if (projectGroup)
entries.GroupBy(e=>e.Project.Id);

if (clientGroup)
entries.GroupBy(e=>e.Client.Id);

if (userGroup)
entries.GroupBy(e=>e.User.Id);
// and all other combinations possible

}

解决方案

Please, check this: Linq GroupByMany dynamically – Mitsu's blog[^]

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