MVC5 SQL左加入查詢

Question

我有2個表稱爲類別和票，我想使用這兩個表已經在我的數據庫中，使我的統計表。

我已經成功創建了類別列，但我不知道如何使我的票證發佈列工作。

我的票證發行欄基本上將所有票據分類到各自的類別並對其進行計數。

我需要在HomeController中編寫代碼，以便我可以將兩個表中的CategoryID鏈接在一起，並在About.cshtml中將鏈接顯示在關於頁面上。

HomeController.cs < --Need修改代碼在這裏

public ActionResult About() 
{ 
    var data = from category in db.Categories 
       group category by category.Title into categoryGroup 
       select new CategoryGroup() 
       { 
        Title = categoryGroup.Key, 
        CategoryCount = categoryGroup.Count() <-- ***This needs to change into Count of Tickets which have the same category ID*** 
       }; 
    return View(data); 
} 

的ViewModels \ CategoryGroup

public class CategoryGroup 
    { 
     public int CategoryID { get; set; } 
     public int CategoryCount { get; set; } 
     public string Title { get; set; } 
    } 

About.cshtml

@model IEnumerable<RecreationalServicesTicketingSystem.ViewModels.CategoryGroup> 

@{ 
    ViewBag.Title = "Ticket Statistics"; 
} 

<h2>Ticket Category Statistics</h2> 

<table> 
    <tr> 
     <th> 
      Category 
     </th> 
     <th> 
      Tickets Issued 
     </th> 
    </tr> 

@foreach (var item in Model) { 
    <tr> 
     <td> 
      @Html.DisplayFor(modelItem => item.Title)   
     </td> 
     <td> 
      @item.CategoryCount @*Instead of Category Count I want numbers of tickets that have been issued for certain IDs. *@ 
     </td> 
    </tr> 
} 
</table> 

僅參考

票務類

public enum Priority 
    { 
     Low,Med,High 
    } 

public class Ticket 
{ 
    public int TicketID { get; set; } 
    public int CategoryID { get; set; } 
    public int UserID { get; set; } 
    public string Issue { get; set; } //A line for our issue like enrollment date in student 
    public Priority? Priority { get; set; } 

    public virtual Category Category { get; set; } 
    public virtual User User { get; set; } 
} 

範疇類

public class Category 
{ 
    [DatabaseGenerated(DatabaseGeneratedOption.None)] 
    public int CategoryID { get; set; } 
    public string Title { get; set; } 

    public virtual ICollection<Ticket> Tickets { get; set; } 
} 

Answer 1

var data = from category in db.Categories 
      select new CategoryGroup() 
      { 
       CategoryID = category.CategoryID, 
       Title = category.Title, 
       CategoryCount = category.Tickets.Count() 
      };