ASP.NET LINQ 查询用于过滤和循环多个表

我有两个单独的域模型类“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 及其属性的所有应用程序的 JSON 输出，嵌套在按其 GroupOrder 属性排序的关联 AgeGroup 中

必需的 JSON 输出结构示例

"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" Class

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; }

In the “年龄组.cs”班级，我有以下

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

并在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);
    }

它给了我正确的输出，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...

Try this

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"
        }
    ]
}
]

希望对你有帮助。