up vote 2 down vote favorite

I would have my JSON string as below which needs to be deserialized to the below class

{
    "Id":"1",
    "Names":{
        "string":"Surya"
    },
    "ClassTypes":{
        "Types":[
            {
                "TypeId":"1",
                "TypeName":"First Name"
            },
            {
                "TypeId":"2",
                "TypeName":"Last Name"
            }
        ]
    },
    "Status":"1",
    "DOB":"23/12/2014"
}

Class Definition

public class MyClass
{
    public int Id { get; set; }
    public IList<string> Names { get; protected set; }
    public IList<Types> ClassTypes { get; protected set; }
    public StatusType Status { get; set; }
    public DateTime DOB { get; set; }

    public MyClass()
    {
        Names = new List<string>();
        ClassTypes = new List<Types>();
        Status = StatusType.Active;
    }
}
public class Types
{
    public int TypeId { get; set; }
    public string TypeName { get; set; }
}

public enum StatusType
{
    Active = 0,
    InActive = 1
}

I have used the following code for deserialization, but getting error

var serializerSettings = new JsonSerializerSettings();
serializerSettings.ContractResolver = new IncludeNonPublicMembersContractResolver();
JsonConvert.DeserializeObject<MyClass>(jsonString, serializerSettings);

public class IncludeNonPublicMembersContractResolver : DefaultContractResolver
{
    public IncludeNonPublicMembersContractResolver()
    {
        DefaultMembersSearchFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
    }
    protected override List<MemberInfo> GetSerializableMembers(Type objectType)
    {
        var members = base.GetSerializableMembers(objectType);
        return members.Where(m => !m.Name.EndsWith("k__BackingField")).ToList();
    }

}

Error Details

Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.IList`1[System.String]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.

To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. 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.

Path 'Names.string', line 1, position 28.

Note - I can't change by JSON string and solution to be more generic has this would be required for other classes as well :(

share|improve this question
up vote 2 down vote accepted

One way is to use a JsonConverter:

  public class MyClass
    {
        public int Id { get; set; }
        [JsonProperty("Names"), JsonConverter(typeof(NamesConverter))]
        public IList<string> Names { get; protected set; }
        [JsonProperty("ClassTypes"), JsonConverter(typeof(TypesConverter))]
        public IList<Types> ClassTypes { get; protected set; }
        public StatusType Status { get; set; }
        [JsonProperty("DOB"), JsonConverter(typeof(DateTimeConverter))]
        public DateTime DOB { get; set; }

        public MyClass()
        {
            Names = new List<string>();
            ClassTypes = new List<Types>();
            Status = StatusType.Active;
        }

        public override string ToString()
        {
            return
                string.Format("ID: {0}\nNames:\n{1}\nClassTypes:\n{2}Status: {3}\nDOB: {4}",
                Id, string.Join("\n", Names), string.Join("\n", ClassTypes), Status, DOB);
        }
    }
    public class Types
    {
        public int TypeId { get; set; }
        public string TypeName { get; set; }

        public override string ToString()
        {
            return string.Format("\tTypeId: {0}\n\tTypeName: {1}\n", TypeId, TypeName);
        }
    }

    public enum StatusType
    {
        Active = 0,
        InActive = 1
    }

    class NamesConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return typeof(Dictionary<string, string>).IsAssignableFrom(objectType);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            return serializer.Deserialize<Dictionary<string, string>>(reader).Values.ToList();
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }

    }
    class TypesConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return typeof(Dictionary<string,List<Types>>).IsAssignableFrom(objectType);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            return serializer.Deserialize<Dictionary<string,List<Types>>>(reader)
                .Values.First().ToList();
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }

    }
    class DateTimeConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return typeof(string).IsAssignableFrom(objectType);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            return DateTime.ParseExact(serializer.Deserialize<string>(reader), @"dd\/MM\/yyyy", null);
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }

    }

...

    var jsonobj = JsonConvert.DeserializeObject<MyClass>(json);
    Console.WriteLine(jsonobj);

Print:

Names:
Surya
ClassTypes:
    TypeId: 1
    TypeName: First Name

    TypeId: 2
    TypeName: Last Name
Status: InActive
DOB: 12/23/2014 12:00:00 AM

https://dotnetfiddle.net/EfQuET

Two way - parse json, but then you need to change the access for the properties Names,ClassTypes or add the constructor:

var jObject = JObject.Parse(json);
var names = new List<string> 
{ 
    jObject["Names"].Value<string>("string")
};
var types = jObject["ClassTypes"]["Types"]
    .Select(x => new Types
    {
        TypeId = x.Value<int>("TypeId"),
        TypeName = x.Value<string>("TypeName")
    })
        .ToList();
var data = new MyClass(names,types)
{
    Id = jObject.Value<int>("Id"),
    Status = (StatusType)Enum.Parse(typeof(StatusType),jObject.Value<string>("Status")),
    DOB = DateTime.ParseExact(jObject.Value<string>("DOB"), @"dd\/MM\/yyyy", null)
};

Console.WriteLine(data);

https://dotnetfiddle.net/HcPxT9

share|improve this answer
up vote 2 down vote

Names is not an array, it's an object:

public class Names
{
    public string @string { get; set; }
}

public class Type
{
    public string TypeId { get; set; }
    public string TypeName { get; set; }
}

public class ClassTypes
{
    public List<Type> Types { get; set; }
}

public class MyClass
{
    public int Id { get; set; }
    public Names Names { get; set; }
    public ClassTypes ClassTypes { get; set; }
    public string Status { get; set; }
    public string DOB { get; set; }
}
...

var result = JsonConvert.DeserializeObject<MyClass>(jsonString);

Classes created by http://json2csharp.com/

share|improve this answer
1  
Upvote for json2csharp :) – niksofteng Sep 28 '15 at 5:55
    
I was looking for code to deserialize the JSON string to the class object – suryakiran Sep 28 '15 at 6:19
    
@suryakiran and why my answer does not help you? – Backs Sep 28 '15 at 6:22
    
because can't even modify my classes as well – suryakiran Sep 28 '15 at 6:24
1  
Use an intermediate class (as outlined in the answer) and manually copy the data into the flat arrays of your desired class. You got the problem of the class and the JSON structure not matching. You could also modify the JSON text. – Andreas Reiff Sep 28 '15 at 7:28

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