c# - 如何返回自定义匿名类型？

Question

如何返回取决于字段参数的匿名类型，其中列出了必须包含在匿名类型中的属性？任务实体有 20 多个属性，客户希望收到不同的属性组合。

public class Test
{
    public class Task
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        //... more 20 properties
    }

    public List<Task> Tasks = new List<Task>();

    public Test()
    {
        Tasks.Add(new Task { Id = 1, Name = "Task #1", Description = "Description task #1" });
        Tasks.Add(new Task { Id = 2, Name = "Task #2", Description = "Description task #2" });
        Tasks.Add(new Task { Id = 3, Name = "Task #3", Description = "Description task #3" });
    }

    public IEnumerable<object> GetAllTasks(string fields)
    {
        //if fields == 'Id,Name' then return anonymous type new { Id = t.Id, Name = t.Name }
        return Tasks.Select(t => new { Id = t.Id, Name = t.Name });

        //if fields == 'Id,Name,Description' then return anonymous type new { Id = t.Id, name = t.Name, Description = t.Description }
        return Tasks.Select(t => new { Id = t.Id, Name = t.Name, Description = t.Description });
    }
}

Answer 1

希望对你有帮助

public List<Task> Tasks = new List<Task>();

public void Test()
{
    Tasks.Add(new Task { Id = 1, Name = "Task #1", Description = "Description task #1" });
    Tasks.Add(new Task { Id = 2, Name = "Task #2", Description = "Description task #2" });
    Tasks.Add(new Task { Id = 3, Name = "Task #3", Description = "Description task #3" });
}

public ActionResult Index()
{
    Test();

    return Json(GetAllTasks(), JsonRequestBehavior.AllowGet);
}

public IEnumerable<object> GetAllTasks()
{
    return Tasks.Select(GetTask);
}

private object GetTask(Task task)
{
    dynamic expandoObject = new ExpandoObject();
    //your if statment block
    if (task.Id == 1)
    {
        expandoObject.Id = task.Id;
    }

    expandoObject.Name = task.Name;
    expandoObject.Description = task.Description;

    var dictionary = expandoObject as IDictionary<string, object>;
    return dictionary.ToDictionary(item => item.Key, item => item.Value);
}

查看结果:

[
   [
      {
         "Key":"Id",
         "Value":1
      },
      {
         "Key":"Name",
         "Value":"Task #1"
      },
      {
         "Key":"Description",
         "Value":"Description task #1"
      }
   ],
   [
      {
         "Key":"Name",
         "Value":"Task #2"
      },
      {
         "Key":"Description",
         "Value":"Description task #2"
      }
   ],
   [
      {
         "Key":"Name",
         "Value":"Task #3"
      },
      {
         "Key":"Description",
         "Value":"Description task #3"
      }
   ]
]