c# - 用于筛选和循环遍历多个表的 ASP.NET LINQ 查询

Question

我有两个独立的域模型类“App”和“AgeGroup”。 App 类包含一些基本的整数和字符串属性，AgeGroup 类也是如此。

我想要实现的是 AppOrder 的所有应用程序及其属性的 JSON 输出，这些应用程序嵌套在按其 GroupOrder 属性排序的关联 AgeGroup 中

必需的示例 JSON 输出结构

"Looped List of Age Groups, order by GroupOrder"
      "Looped List of Apps, order by App Order"

 First Age Group
    Foo App Name
        Foo App Icon
        Foo App Store URL
    Bar App Name
        Bar App Icon
        Bar App Store URL
 Second Age Group
    Tur App Name
        Tur App Icon
        Tur App Store URL
    Puk App Name
        Puk App Icon
        Puk App Store URL
  and so on...

到目前为止我的方法:

这是我的“App.cs”类

public int Id { get; set; }
public string Name { get; set; }
public string StoreURL { get; set; }
public int AppOrder { get; set; }
public string AppIcon { get; set; }

public AgeGroup AgeGroup { get; set; }    // Linked to AgeGroup Class
public int AgeGroupId { get; set; }

在 "AgeGroup.cs" 类中，我有以下内容

public int Id { get; set; }
public int GroupOrder { get; set; }
public string Name { get; set; }

并且在 AppsController.cs

    [HttpGet]
    [Route("api/groups")]

    public IHttpActionResult AppsByGroup ()
    {
        var apps = _context.Apps
            .OrderBy(a => a.AppOrder)
            .Select(a => new
            {
                a.Name,
                a.StoreURL,
                a.AppIcon,
                AgeGroup = a.AgeGroup.Name
            }).GroupBy(a => a.AgeGroup);

       return Json(apps);
    }

它为我提供了正确的输出，但没有年龄组名称。

[
  [ // Here I wanted the AgeGroup Name from the AgeGroup Table (Group A)
    {
        "Name": "First App for Group A",
        "StoreURL": "some string",
        "AppIcon": "icon string",
        "AgeGroup": "Group A"
    },
    {
        "Name": "2nd App Group A",
        "StoreURL": "aslfdj",
        "AppIcon": "asljf",
        "AgeGroup": "Group A"
    },
    {
        "Name": "3rd App Group A",
        "StoreURL": "aslfdj",
        "AppIcon": "alsfdj",
        "AgeGroup": "Group A"
    }
  ],
  [ // Here I wanted the AgeGroup Name from the AgeGroup Table (Group B)
    {
        "Name": "1st App GroupB",
        "StoreURL": "alsfdj",
        "AppIcon": "alsdjf",
        "AgeGroup": "Group B"
    },

//and so on...

Answer 1

试试这个

public IHttpActionResult AppsByGroup() {

   var apps = _context.Apps.OrderBy(a => a.AppOrder);
   var groups = _context.AgeGroups.OrderBy(g => g.GroupOrder);

   var result = groups.Select(x => new {
         AgeGroupName = x.Name,
         Apps = apps
           .Where(y => x.Id == y.AgeGroupId)
           .Select(y => new {
              AppName = y.Name,
              AppIcon = y.AppIcon,
              StoreURL = y.StoreURL
            })
         });

   return Json(result);
}

它给出以下输出

[
{
    "AgeGroupName": "Group C",
    "Apps": [
        {
            "AppName": "C Group App",
            "AppIcon": "Some string",
            "StoreURL": "64"
        }
    ]
},
{
    "AgeGroupName": "Group A",
    "Apps": [
        {
            "AppName": "App 2nd for Group AA",
            "AppIcon": "Some string",
            "StoreURL": "654"
        },
        {
            "AppName": "App 1 for Group A",
            "AppIcon": "Some string",
            "StoreURL": "654"
        }
    ]
},
{
    "AgeGroupName": "Group B",
    "Apps": [
        {
            "AppName": "App 1 for Group B",
            "AppIcon": "Some string",
            "StoreURL": "31"
        }
    ]
}
]

希望对您有所帮助。