save a string in dictionary-CodePudding

I have in following string:

[{"key":"cod1","value":["RR4","RR6"]},{"key":"cod2","value":["RR2","RR3"]},{"key":"cod3","value":["RR1","RR2"]}]

and I want to save it in a dictionary like this:

Dictionary<string, List>

The project is made in C# and to try to do it I use the following statement:

Dictionary<string, List<string>> dic = new Dictionary<string, List<string>>();
dic = Newtonsoft.Json.JsonConvert.DeserializeObject<Dictionary<string, List<string>>>(ss);

But I get this error:

"Newtonsoft.Json.JsonSerializationException: Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'System.Collections.Generic.Dictionary2[System.String,System.Collections.Generic.List1[System.String]]' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.\r\nTo fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.\r\nPath '', line 1, position 1.\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.EnsureArrayContract(JsonReader reader, Type objectType, JsonContract contract)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateList(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue, String id)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)\r\n at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)\r\n at Newtonsoft.Json.JsonSerializer.Deserialize(JsonReader reader, Type objectType)\r\n at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)\r\n at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)\r\n at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value)\r\n at operationWebAPI.Repository.TransferLadleRepository.LastEvents() in C:\Users\raulm\Documentos\Proyectos\SOSteelShop\Backend\operationWebAPI\Repository\TransferLadleRepository.cs:line 1164\r\n at operationWebAPI.Controllers.TransferLadleController.GetLastEvents() in C:\Users\raulm\Documentos\Proyectos\SOSteelShop\Backend\operationWebAPI\Controllers\TransferLadleController.cs:line 229"

I can't find how to solve the problem. Can you help me? Thanks a lot!!

CodePudding user response：

JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array

Not sure if it will work but you can try that

JsonArrayAttrribute Usage in C# Code ( Json.Net )

CodePudding user response：

The thing you're trying to deserialize is not a dictionary. It's an array/object. Try something like this:

var json = @"[{""key"":""cod1"",""value"":[""RR4"",""RR6""]},{""key"":""cod2"",""value"":[""RR2"",""RR3""]},{""key"":""cod3"",""value"":[""RR1"",""RR2""]}]";

var objects = JsonConvert.DeserializeObject<List<Obj>>(json);

where Obj looks like this:

public class Obj
{
  [JsonProperty("key")]
  public string Key { get; set; }
  
  [JsonProperty("value")]
  public List<string> Value { get; set; }
}

CodePudding user response：

Your root json element is array, so the data can be represented as collection of Dictionary<string, JToken>:

var result = JsonConvert.DeserializeObject<List<Dictionary<string, JToken>>>(json);

But I suggest to introduce a class representing data and processing it correspondingly:

public class Root
{
    [JsonProperty("key")]
    public string Key { get; set; }

    [JsonProperty("value")]
    public List<string> Value { get; set; }
}

Root myDeserializedClass = JsonConvert.DeserializeObject<List<Root>>(json);