在C＃ASP .NET Core中将JSON反序列化为IEnumerable

Question

I have a json object. I want to deserialize it to an object of the IEnumerable type.

I am working in asp.net Core.

I am tried by this:

IEnumerable div = (IEnumerable)JsonConvert.DeserializeObject(value, typeof(IEnumerable));

Here value is the json variable.

I got this type of exception:

Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the current JSON object (eg {"name":"value"}) into type 'System.Collections.IEnumerable' because the type requires a JSON array (eg [1,2,3]) to deserialize correctly. To fix this error either change the JSON to a JSON array (eg [1,2,3]) or change the deserialized type so that it is a normal .NET type (eg not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.

Json File:

{
  "name": "xx",
  "place": {
    "native": "aa",
    "school": "ee",
    "college": "dd"
  },
  "dob": "ss",
  "ids": [
    0,
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    9,
    10,
    11,
    12,
    13,
    14,
    15,
    16,
    17,
    18,
    19,
    20,
    21,
    22,
    23,
    24,
    25,
    26,
    27,
    28,
    29,
    30,
    31,
    32,
    33,
    34,
    35,
    36,
    37,
    38,
    39,
    40,
    41,
    42,
    43,
    44,
    45,
    46,
    47,
    48,
    49,
    50,
    51,
    52,
    53,
    54,
    55,
    56,
    57,
    58,
    59,
    60,
    61,
    62,
    63,
    64,
    65,
    66,
    67,
    68,
    69,
    70,
    71,
    72,
    73,
    74,
    75,
    76,
    77,
    78,
    79,
    80,
    81,
    82,
    83,
    84,
    85,
    86,
    87,
    88,
    89,
    90,
    91,
    92,
    93,
    94,
    95,
    96,
    97,
    98,
    99,
    100,
    101,
    102,
    103,
    104,
    105,
    106,
    107,
    108,
    109,
    110,
    111,
    112,
    113,
    114,
    115,
    116,
    117,
    118,
    119,
    120
  ],
  "mark": [
    {
      "10thmark": "345",
      "12thmark": "1100"
    },
    {
      "Diploma": "G",
      "Diploma PG": "R"
    },
    {
      "Ug": "D",
      "PG": "E"
    }
  ]
}

How to resolve this?

Answer 1

1) If your json is an object eg MyUser

public class MyUser
{
    public int Id { get; set; }    
    public string Name { get; set; }    
    public string Description { get; set; }
}

and your json is

{
   "Id": 1,
   "Name": "Andrew",
   "Description": "Software Engineer"
}

then you easily deserialize by using below code

MyUser user = JsonConvert.DeserializeObject<MyUser>(data);

"data" in above code is your json file data.

2) If your json is an array of object like eg Array of MyUser.

{
  "Users": [
    { "Id": 1, "Name": "Andrew", "Description": "Software Engineer"},
    { "Id": 2, "Name": "Eddy", "Description": "Software Developer"},
    { "Id": 3, "Name": "Matthew", "Description": "Web Developer"}
  ]
}

then you need a view model of IEnumerable type property MyUser to deserialize like

public class MyUserVM
{
    public IEnumerable<MyUser> Users { get; set; }
}

and then you need to deserialize by using above view model like

MyUserVM users = JsonConvert.DeserializeObject<MyUserVM>(data);

"data" in above code is your json file data.

Q) Why the need of view model here?

A) Because json is an key value format text based data and you need a key to read it in JsonConvert class.

Edited:

you please change your json keys like below

{
  "name": "xx",
  "place": {
    "native": "aa",
    "school": "ee",
    "college": "dd"
  },
  "dob": "ss",
  "ids": [
    0,
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    9,
    10,
    11,
    12,
    13,
    14,
    15,
    16,
    17,
    18,
    19,
    20,
    21,
    22,
    23,
    24,
    25,
    26,
    27,
    28,
    29,
    30,
    31,
    32,
    33,
    34,
    35,
    36,
    37,
    38,
    39,
    40,
    41,
    42,
    43,
    44,
    45,
    46,
    47,
    48,
    49,
    50,
    51,
    52,
    53,
    54,
    55,
    56,
    57,
    58,
    59,
    60,
    61,
    62,
    63,
    64,
    65,
    66,
    67,
    68,
    69,
    70,
    71,
    72,
    73,
    74,
    75,
    76,
    77,
    78,
    79,
    80,
    81,
    82,
    83,
    84,
    85,
    86,
    87,
    88,
    89,
    90,
    91,
    92,
    93,
    94,
    95,
    96,
    97,
    98,
    99,
    100,
    101,
    102,
    103,
    104,
    105,
    106,
    107,
    108,
    109,
    110,
    111,
    112,
    113,
    114,
    115,
    116,
    117,
    118,
    119,
    120
  ],
  "mark": [
    {
      "tenthmark": "345",
      "twelthmark": "1100"
    },
    {
      "Diploma": "G",
      "DiplomaPG": "R"
    },
    {
      "Ug": "D",
      "PG": "E"
    }
  ]
}

and use below view models that i created for you

public class Place
{
    public string native { get; set; }
    public string school { get; set; }
    public string college { get; set; }
}

public class Mark
{
    public string tenthmark { get; set; }
    public string twelthmark { get; set; }
    public string Diploma { get; set; }
    public string DiplomaPG { get; set; }
    public string Ug { get; set; }
    public string PG { get; set; }
}

public class RootObject
{
    public string name { get; set; }
    public Place place { get; set; }
    public string dob { get; set; }
    public List<int> ids { get; set; }
    public List<Mark> mark { get; set; }
}

and then deserialize by using

RootObject rootObject = JsonConvert.DeserializeObject<RootObject>(data);

Answer 2

您不能反序列化为接口，只能反序列化为具体类型，例如List of T

Answer 3

您不仅可以反序列化为IEnumerable，还需要一个模型来放入数据。您需要一个能够反映JSON结构的ViewModel，然后可以轻松地反序列化为您的ViewModel类型的IEnumerable。

JsonConvert.DeserializeObject<IEnumerable<SomeViewModel>>(jsonData)