错误与Brewerydb API

Question

我试图使用JSON我的第一个API调用来收集啤酒厂信息，并收到以下错误读取JSON数据：

An unhandled exception of type 'Newtonsoft.Json.JsonSerializationException' occurred in Newtonsoft.Json.dll

Additional information: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[Brewery.Adjunct]' 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 'message', line 1, position 11.

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
using Newtonsoft.Json; 
using Newtonsoft.Json.Converters; 

namespace Brewery 
{ 
class Adjunct 
{ 
    //properties 
    public int id { get; set; } 

    public string name { get; set; } 

    public string description { get; set; } 

    public string category { get; set; } 

    public string catDisplay { get; set; } 

    //create list of Adjunct objects 
    public List<Adjunct> adjuncts{ get; set; } 

    //address with query for all adjunct items 
    const string address = "http://api.brewerydb.com/v2/?[MY KEY]/adjunct"; 


    //fill adjuncts with deserialized json data 
    public void GetBeer(string beer) 
    { 
     //initialize beer list 
     adjuncts = new List<Adjunct>(); 

     //build connection with query and return string 
     //***static class Connect uses System.net to create web request and web response objects*** 
     string result = Connect.GetConnection(address); 

     //get list of Adjunct objects 
     adjuncts = JsonConvert.DeserializeObject<List<Adjunct>>(result); 
    } 


    //get Adjunct string 
    public string PrintData(string sep) 
    { 
     return "name: " + name + sep + "id: " + id + sep + "description: " + description; 
    } 


    //search adjunct by id 
    public Adjunct AdjunctByID(int _id) 
    { 
     foreach (Adjunct ad in adjuncts) 
     { 
      if (_id == id) 
      { 
       return ad; 
      } 
     } 
     return null; 
    } 
} 

我需要使用不同的JSON.NET方法？

Answer 1

基础上brewerydb documentation你的类应该是这样的：

public class Adjunct 
{ 
    public int id { get; set; } 
    public string name { get; set; } 
    public string category { get; set; } 
    public string categoryDisplay { get; set; } 
    public string createDate { get; set; } 
} 

public class AdjunctsReply 
{ 
    public int currentPage { get; set; } 
    public int numberOfPages { get; set; } 
    public int totalResults { get; set; } 
    public List<Adjunct> adjuncts { get; set; } 
    public string status { get; set; } 
} 

，您将可以反序列化JSON像这样：

reply = JsonConvert.DeserializeObject<AdjunctsReply>(result); 

例如：

public void GetBeer(string beer) 
{ 
    //initialize beer list 
    AdjunctsReply reply; 

    //build connection with query and return string 
    //***static class Connect uses System.net to create web request and web response objects*** 
    string result = Connect.GetConnection(address); 

    //get list of Adjunct objects 
    reply = JsonConvert.DeserializeObject<AdjunctsReply>(result); 

    foreach(var adjunct in reply.adjuncts) 
    { 
     Console.WriteLine(adjunct.name); 
    } 
} 

编辑 充分运作的例子。只需插入密钥并将其作为控制台应用程序运行即可。

using System; 
using System.Collections.Generic; 
using System.Net; 
using Newtonsoft.Json; 

namespace WebClientDownloadMp4 
{ 
    class Program 
    { 
     static void Main(string[] args) 
     { 
      // Insert your key here 
      var key = "0000000000000000000000000000"; 

      var client = new WebClient(); 
      var reply = client.DownloadString(@"http://api.brewerydb.com/v2/adjuncts?key=" + key); 
      var adjunctsReply = JsonConvert.DeserializeObject<AdjunctsReply>(reply); 
      Console.WriteLine("Current page: " + adjunctsReply.currentPage); 
      Console.WriteLine("Total pages: " + adjunctsReply.numberOfPages); 
      Console.WriteLine("Total results: " + adjunctsReply.totalResults); 
      foreach (var adjunct in adjunctsReply.Adjuncts) 
      { 
       Console.WriteLine("Id {0}: {1}", adjunct.id, adjunct.name); 
      } 
     } 
    } 

    public class Adjunct 
    { 
     public int id { get; set; } 
     public string name { get; set; } 
     public string category { get; set; } 
     public string categoryDisplay { get; set; } 
     public string createDate { get; set; } 
    } 

    public class AdjunctsReply 
    { 
     public int currentPage { get; set; } 
     public int numberOfPages { get; set; } 
     public int totalResults { get; set; } 
     [JsonProperty("data")] 
     public List<Adjunct> Adjuncts { get; set; } 
     public string status { get; set; } 
    } 
}