無法通過LINQ

Question

組後，保留財產我有用途的集合，如下所示，需要下面的輸出如下：

這是我的用法類：

public class Usage 
{ 
    public Usage() {} 
    public string Alias { get; set; } 
    public int ActivityCount { get; set; } 
    public DateTime HitDate { get; set; } 

} 

這是我的代碼：

我想先集合到用戶和每個用戶，我想要得到每天的點擊數，如下面的預期輸出中所示。請注意，日期時間a和d是同一天的不同時間，因此需要將它們組合在一起。

此我將用它來繪製成命中條形圖VS日期即每天

擊中這樣做，我無法別名字段的數據保存到我的第二個級別分組：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Text.RegularExpressions; 
using System.Threading.Tasks; 

namespace NullOperator 
{ 
    class Program 
{ 
    static void Main(string[] args) 
    { 
     var a = new DateTime(2015, 10, 23, 12, 05, 06); 
     var b = new DateTime(2015, 10, 24, 12, 05, 06); 
     var c = new DateTime(2015, 10, 25, 12, 05, 06); 
     var d = new DateTime(2015, 10, 23, 14, 05, 06); 

     var usages = new List<Usage> 
     { 
      new Usage{Alias = "A ",HitDate = a}, 
      new Usage{Alias = "A ",HitDate = a}, 
      new Usage{Alias = "A ",HitDate = d}, 
      new Usage{Alias = "A ",HitDate = b}, 
      new Usage{Alias = "A ",HitDate = b}, 
      new Usage{Alias = "A ",HitDate = b}, 
      new Usage{Alias = "A ",HitDate = c}, 


      new Usage{Alias = "B ",HitDate = a}, 
      new Usage{Alias = "B ",HitDate = b}, 
      new Usage{Alias = "B ",HitDate = b}, 
      new Usage{Alias = "B ",HitDate = c}, 
      new Usage{Alias = "B ",HitDate = c}, 
      new Usage{Alias = "B ",HitDate = c}, 

      new Usage{Alias = "C ",HitDate = a}, 
      new Usage{Alias = "C ",HitDate = a}, 
      new Usage{Alias = "C ",HitDate = a}, 
      new Usage{Alias = "C ",HitDate = c}, 
      new Usage{Alias = "C ",HitDate = c}, 
      new Usage{Alias = "C ",HitDate = c}, 
     }; 

     var g = usages.GroupBy(r => r.Alias); 

     foreach (var u in g) 
     {   
      var x = u.GroupBy(r => r.HitDate.Day).Select(gr=>new 
      { 
       HitDate=gr.Key, 
       Count=gr.Count() 
      }); 

      foreach (var m in x) 
      { 
       Console.WriteLine(m.HitDate + " " +m.Count); 
      } 
     } 

     Console.Read(); 
    } 
} 

//預期輸出

Alias : HitDate.Date : hitcount 
// A - 23/10/2015 - 3 
// A - 24/10/2015 - 3 
// A - 25/10/2015 - 1 

// B - 23/10/2015 - 1 
// B - 24/10/2015 - 2 
// B - 25/10/2015 - 3 

// C - 23/10/2015 - 3 
// C - 24/10/2015- 0 
// C - 25/10/2015 - 3 

下的輸出：

23 3 
24 3 
25 1 
23 1 
24 2 
25 3 
23 3 
25 3 

正如你所看到的，分組是可以的，但像整個Date和Alias這樣的信息會丟失，並且無法在嵌套循環的代碼中檢索它們。

對此有何建議？關於如何獲得所需的輸出？

Answer 1

基本上有兩個問題在這裏：

• 你被Day分組而不是Date，我疑問你想要做
• 你不使用的事實，你已經有別名作爲外部分組的鑰匙

你實際上可以 - 您使用的類可以有一個體是三線

var query = usages.GroupBy(r => new { r.Alias, r.HitDate.Date }, 
          (key, elements) => new { key.Alias, 
                key.Date, 
                Count = elements.Count() }) 
        .OrderBy(x => x.Alias) 
        .ThenBy(x => x.Date); 

foreach (var item in query) 
{ 
    Console.WriteLine("{0} {1} {2}", item.Alias, item.Date, item.Count); 
} 

Answer 2

您也可以在select語句中選擇值。

var g = usages.GroupBy(r => r.Alias); 
foreach (var u in g) 
{ 
    var x = u.GroupBy(r => r.HitDate.Day) 
      .Select(gr => new { 
            Alias=u.Alias, 
            HitDate=gr.Key, 
            Count=gr.Count() 
      }); 
    foreach (var m in x) 
    { 
     Console.WriteLine(m.HitDate + " " + m.Count); 
    } 
}