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c#xamarin.formsxamarin.androidrefit

Error: Newtonsoft.Json.JsonSerializationException


Hello, I am learning to use Refit and I have a problem.

these are the models

public partial class Source
    {
        [JsonProperty("id")]
        public string Id { get; set; }

        [JsonProperty("name")]
        public string Name { get; set; }
    }

    public partial class Article
    {
        [JsonProperty("source")]
        public Source Source { get; set; }

        [JsonProperty("author")]
        public string Author { get; set; }

        [JsonProperty("title")]
        public string Title { get; set; }

        [JsonProperty("description")]
        public string Description { get; set; }

        [JsonProperty("url")]
        public Uri Url { get; set; }

        [JsonProperty("urlToImage")]
        public Uri UrlToImage { get; set; }

        [JsonProperty("publishedAt")]
        public DateTimeOffset PublishedAt { get; set; }

        [JsonProperty("content")]
        public string Content { get; set; }
    }

This is the interface with the request and its parameters.

    public interface IRest
    {
        [Get("/v2/top-headlines")]
        Task<List<Article>> GetArticles(string country, string apiKey"RemovingKey");
    }

This is the Request in the ArticleViewModel

        private  async Task GetTaskAsync()
        {
            var WeApp = RestService.For<IRest>("https://newsapi.org/");
            var result = await WeApp.GetArticles("co");
        }

When I debug to see the data this comes out

Newtonsoft.Json.JsonSerializationException
  Message=Cannot deserialize the current JSON object (e.g. {"name":"value"}) 
into type 'System.Collections.Generic.List`1[RefitNpt.Models.Article]'
 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<T>) 
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 'status', line 1, position 10.

I've been looking for solutions but I haven't been able to solve them, I'm learning independently.


Solution

  • You need another class that will serve as the RootObject for your json response.

    public class Articles
    {
      public string status {get; set;}
      public int totalResults {get;set;}
      public List<Article> articles {get;set; }
    }
    

    and then use this in your IRest controller, (You will need to update your method (GetArticles) to return Articles instead of List<Article> as well.

    Task<Articles> GetArticles(string country, string apiKey);
    

    This response is aligned with following json snippet that comes from the site https://newsapi.org

    {
      "status": "ok",
      "totalResults": 3152,
      "articles": [
        {
          "source": {
            "id": null,
            "name": "Business 2 Community"
          },
          "author": "Gurbaj Singh",
          "title": "Investing in Cryptocurrency? What are the Odds!?",
          "description": "Cryptocurrency has become the most profitable object for investing money. At the same time, in comparison with precious metals, natural…",
          "url": "https://www.business2community.com/finance/investing-in-cryptocurrency-what-are-the-odds-02326876",
          "urlToImage": "https://cdn.business2community.com/wp-content/uploads/2020/07/Untitled-design-3.png",
          "publishedAt": "2020-07-13T15:30:31Z",
          "content": "Cryptocurrency has become the most profitable object for investing money. At the same time, in comparison with precious metals, natural resources, or real estate, virtual coins involve more risks ass… [+9899 chars]"
        },
        // More Articles here...
      ]
    }