转换一个JavaScriptConverter到JSON.NET JsonConverter

Question

我需要重写下面的类的Json.Net JsonConverter以获取代码与Xamarin单工作的android

private class ResourceConverter : JavaScriptConverter 
    { 
     public ResourceConverter() { } 

     public override IEnumerable<Type> SupportedTypes 
     { 
      get { return new ReadOnlyCollection<Type>(new List<Type>(new Type[] { typeof(SystemCertificate) })); } 
     } 

     public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer) 
     { 
      if (dictionary.ContainsKey("Certificate")) 
      { 
       SystemCertificate customerResource = new SystemCertificate(); 
       customerResource.SystemID = dictionary["SystemID"].ToString(); 
       string base64Text = dictionary["Certificate"].ToString(); 
       customerResource.Certificate = Convert.FromBase64CharArray(base64Text.ToCharArray(), 0, base64Text.Length); 
       return customerResource; 
      } 
      return null; 
     } 

     public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer) 
     { 
      if (obj is SystemCertificate) 
      { 
       SystemCertificate systemCertificate = obj as SystemCertificate; 
       Dictionary<string, object> dic = new Dictionary<string, object>(); 
       dic.Add("SystemID", systemCertificate.SystemID); 
       return dic; 
      } 
      return null; 
     } 
    } 

问题是JsonConverter的基本方法对于序列化（WriteJson）是无效的，我真的不知道该怎么做，请帮助我。

private class ResourceConverterGen2 : JsonConverter 
    { 
     public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) 
     { 
      throw new NotImplementedException(); 
     } 

     public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) 
     { 
      throw new NotImplementedException(); 
     } 

     public override bool CanConvert(Type objectType) 
     { 
      throw new NotImplementedException(); 
     } 
    } 

Answer 1

你需要写它传递给WriteJson方法JsonWriter实例。您可以使用serializer参数来帮助您做到这一点，如下面的代码所示。

public class StackOverflow_15829446 
{ 
    private class ResourceConverterGen2 : JsonConverter 
    { 
     public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) 
     { 
      SystemCertificate systemCertificate = (SystemCertificate)value; 
      Dictionary<string, string> dic = new Dictionary<string, string>(); 
      dic.Add("SystemID", systemCertificate.SystemId); 
      dic.Add("Certificate", Convert.ToBase64String(systemCertificate.Certificate)); 
      serializer.Serialize(writer, dic); 
     } 

     public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) 
     { 
      var dic = serializer.Deserialize<Dictionary<string, string>>(reader); 
      SystemCertificate systemCertificate = new SystemCertificate(); 
      systemCertificate.SystemId = dic["SystemID"]; 
      systemCertificate.Certificate = Convert.FromBase64String(dic["Certificate"]); 
      return systemCertificate; 
     } 

     public override bool CanConvert(Type objectType) 
     { 
      return typeof(SystemCertificate) == objectType; 
     } 
    } 
    public class SystemCertificate 
    { 
     public byte[] Certificate; 
     public string SystemId; 
    } 
    public static void Test() 
    { 
     SystemCertificate cert = new SystemCertificate 
     { 
      SystemId = "123", 
      Certificate = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 } 
     }; 
     JsonSerializer js = new JsonSerializer(); 
     js.Converters.Add(new ResourceConverterGen2()); 
     StringBuilder sb = new StringBuilder(); 
     StringWriter sw = new StringWriter(sb); 
     js.Serialize(sw, cert); 
     Console.WriteLine(sb.ToString()); 
     StringReader sr = new StringReader(sb.ToString()); 
     SystemCertificate cert2 = (SystemCertificate)js.Deserialize(sr, typeof(SystemCertificate)); 
     Console.WriteLine("Id={0},Cert={1}", cert2.SystemId, string.Join(",", cert2.Certificate.Select(b => string.Format("{0:X2}", (int)b)))); 
    } 
}