将JSON对象转换为Data.Entities.Models.MyModel [英] Converting JSON object to Data.Entities.Models.MyModel

问题描述

所以，

我将JSON对象序列化到我的Entity / Model对象有问题。

我有以下代码片段：

  var serializedValue = JsonConvert .SerializeObject（newRows，new MyModelConverter（））; 
 
 var csvToSave = JsonConvert.DeserializeObject&MyModel>（serializedValue）; 
  

其中newRows是一个列表< KeyValuePair< string，string>> / code>

实体看起来像这样：

  public class MyModel：Entity 
 {
 public int Id {get;组; } //主键
 
 public DateTime TouchTime {get;组; } 
 
 public DateTime InstallTime {get;组; } 
 
 public string EventName {get;组; } 
 
} 
  

回顾旧的StackOverflow帖子，我看到我需要使用自定义JsonConverter，以便我可以将我的数据转换为json对象。

这是我的转换器类：

  public class MyModelConverter：JsonCreationConverter&为MyModel> 
 {
 protected override MyModel Create（Type objectType，JObject jObject）
 {
 return new MyModel（）; 
} 
} 
 
 public abstract class JsonCreationConverter< T> ：JsonConverter 
 {
 ///< summary> 
 ///在JSON对象中创建一个基于objectType的属性的实例
 ///< / summary> 
 ///< param name =objectType>对象类型的预期< / param> 
 ///< param name =jObject> 
 ///将反序列化的JSON对象的内容
 ///< / param> 
 ///< returns>< / returns> 
 protected abstract T Create（Type objectType，JObject jObject）; 
 
 public override bool CanConvert（Type objectType）
 {
 return typeof（T）.IsAssignableFrom（objectType）; 
 
 
 public override object ReadJson（JsonReader reader，
 Type objectType，
 object existingValue，
 JsonSerializer serializer）
 {
 //从流
加载JObject JObject jObject = JObject.Load（reader）; 
 
 //基于JObject 
创建目标对象T target = Create（objectType，jObject）; 
 
 //填充对象属性
 serializer.Populate（jObject.CreateReader（），target）; 
 
返回目标; 
} 
 
 public override void WriteJson（JsonWriter writer，
 object value，
 JsonSerializer serializer）
 {
列表< KeyValuePair< string，对象>> list = value作为List< KeyValuePair< string，object>> ;; 
 writer.WriteStartArray（）; 
 foreach（列表中的var项）
 {
 writer.WriteStartObject（）; 
 writer.WritePropertyName（item.Key）; 
 writer.WriteValue（item.Value）; 
 writer.WriteEndObject（）; 
} 
 writer.WriteEndArray（）; 
} 
} 
  

但是当我运行我的程序，我得到这个错误而不是

 不能将当前JSON数组（例如[1,2,3]）反序列化为Data.Entities.Models因为该类型需要一个JSON对象（例如{name：value}）才能正确反序列化。 
  

现在我的Json对象看起来像这样：

  [
 {
键：归属触摸时间，
值：2016-09-06 20:11： 50
}，
 {
密钥：安装时间，
值：2016-09-06 20:14:12
 
 {
Key：事件名称，
值：安装
} 
] 
  

然后我修改了我的转换器：

  public abstract class JsonCreationConverter< T> ：JsonConverter 
 {
 ///< summary> 
 ///在JSON对象中创建一个基于objectType的属性的实例
 ///< / summary> 
 ///< param name =objectType>对象类型的预期< / param> 
 ///< param name =jObject> 
 ///将反序列化的JSON对象的内容
 ///< / param> 
 ///< returns>< / returns> 
 protected abstract T Create（Type objectType，JObject jObject）; 
 
 public override bool CanConvert（Type objectType）
 {
 return objectType == typeof（List< KeyValuePair< string，string>>）; 
 
 
 public override object ReadJson（JsonReader reader，
 Type objectType，
 object existingValue，
 JsonSerializer serializer）
 {
 //从流
加载JObject JObject jObject = JObject.Load（reader）; 
 
 //基于JObject 
创建目标对象T target = Create（objectType，jObject）; 
 
 //填充对象属性
 serializer.Populate（jObject.CreateReader（），target）; 
 
返回目标; 
} 
 
 public override void WriteJson（JsonWriter writer，
 object value，
 JsonSerializer serializer）
 {
列表< KeyValuePair< string，串GT;> list = value作为List< KeyValuePair< string，string>> ;; 
 writer.WriteStartArray（）; 
 foreach（列表中的var项）
 {
 writer.WriteStartObject（）; 
 writer.WritePropertyName（item.Key）; 
 writer.WriteValue（item.Value）; 
 writer.WriteEndObject（）; 
} 
 writer.WriteEndArray（）; 
} 
} 
  

但是我的Json对象现在看起来像这样： p>

  [
 {
归属触摸时间：2016-09-06 20:11:50 
}，
 {
安装时间：2016-09-06 20:14:12
}，
 {
事件名称：安装
}，
（etc ...）//不是JSON的一部分，只需切割它
] 
  pre> 
 
 
哪个是伟大的，但仍然不会映射到我的实体
解决方案
您似乎正在为每个KVP创建一个新的JSON对象，而不是将KVP分组到单个对象中。将 writer.WriteStartObject（）; 和 writer.EndObject（）; 移动到循环外部，然后结束一个很好的JSON对象。
  writer.WriteStartObject（）; 
 
 foreach（列表中的var项）
 {
 
 writer.WritePropertyName（item.Key）; 
 writer.WriteValue（item.Value）; 
 
} 
 
 writer.WriteEndObject（）; 
 writer.WriteEndArray（）; 
  
您需要将这些开始/结束对象带到For循环之外。
 
 
 
所以你应该得到这个... 
  [
 {
归属触摸时间：2016-09-06 20:11:50
安装时间：2016-09-06 20:14:12
事件名称： 安装
}，
] 
  
 
So, 

I'm having an issue with serializing my JSON object to my Entity/Model object. 

I have the following code snippet: 
var serializedValue = JsonConvert.SerializeObject(newRows, new MyModelConverter());

var csvToSave = JsonConvert.DeserializeObject<MyModel>(serializedValue);
Where newRows is a List<KeyValuePair<string,string>>

Where Entity looks something like this: 
public class MyModel: Entity
{
    public int Id { get; set; } //primary key

    public DateTime TouchTime { get; set; }

    public DateTime InstallTime { get; set; }

    public string EventName { get; set; }

}
Looking back at old StackOverflow posts, I see I need to use a custom JsonConverter so that I can get my data to be converted to a json object. 

Here's my converter class: 
public class MyModelConverter : JsonCreationConverter<MyModel>
{
    protected override MyModel Create(Type objectType, JObject jObject)
    {
        return new MyModel();
    }
}

public abstract class JsonCreationConverter<T> : JsonConverter
{
    /// <summary>
    /// Create an instance of objectType, based properties in the JSON object
    /// </summary>
    /// <param name="objectType">type of object expected</param>
    /// <param name="jObject">
    /// contents of JSON object that will be deserialized
    /// </param>
    /// <returns></returns>
    protected abstract T Create(Type objectType, JObject jObject);

    public override bool CanConvert(Type objectType)
    {
        return typeof(T).IsAssignableFrom(objectType);
    }

    public override object ReadJson(JsonReader reader,
                                    Type objectType,
                                     object existingValue,
                                     JsonSerializer serializer)
    {
        // Load JObject from stream
        JObject jObject = JObject.Load(reader);

        // Create target object based on JObject
        T target = Create(objectType, jObject);

        // Populate the object properties
        serializer.Populate(jObject.CreateReader(), target);

        return target;
    }

    public override void WriteJson(JsonWriter writer,
                                   object value,
                                   JsonSerializer serializer)
    {
        List<KeyValuePair<string, object>> list = value as List<KeyValuePair<string, object>>;
        writer.WriteStartArray();
        foreach (var item in list)
        {
            writer.WriteStartObject();
            writer.WritePropertyName(item.Key);
            writer.WriteValue(item.Value);
            writer.WriteEndObject();
        }
        writer.WriteEndArray();
    }
}
But when I run my program, I get this error instead: 
Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'Data.Entities.Models.MyModel' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
Where my Json object looks like this now: 
[  
   {  
      "Key":"Attributed Touch Time",
      "Value":"2016-09-06 20:11:50"
   },
   {  
      "Key":"Install Time",
      "Value":"2016-09-06 20:14:12"
   },
   {  
      "Key":"Event Name",
      "Value":"install"
   }
]
Then I fixed my converter like so: 
public abstract class JsonCreationConverter<T> : JsonConverter
{
    /// <summary>
    /// Create an instance of objectType, based properties in the JSON object
    /// </summary>
    /// <param name="objectType">type of object expected</param>
    /// <param name="jObject">
    /// contents of JSON object that will be deserialized
    /// </param>
    /// <returns></returns>
    protected abstract T Create(Type objectType, JObject jObject);

    public override bool CanConvert(Type objectType)
    {
        return objectType == typeof(List<KeyValuePair<string, string>>);
    }

    public override object ReadJson(JsonReader reader,
                                    Type objectType,
                                     object existingValue,
                                     JsonSerializer serializer)
    {
        // Load JObject from stream
        JObject jObject = JObject.Load(reader);

        // Create target object based on JObject
        T target = Create(objectType, jObject);

        // Populate the object properties
        serializer.Populate(jObject.CreateReader(), target);

        return target;
    }

    public override void WriteJson(JsonWriter writer,
                                   object value,
                                   JsonSerializer serializer)
    {
        List<KeyValuePair<string, string>> list = value as List<KeyValuePair<string, string>>;
        writer.WriteStartArray();
        foreach (var item in list)
        {
            writer.WriteStartObject();
            writer.WritePropertyName(item.Key);
            writer.WriteValue(item.Value);
            writer.WriteEndObject();
        }
        writer.WriteEndArray();
    }
}
But my Json object now looks like this: 
[  
   {  
      "Attributed Touch Time":"2016-09-06 20:11:50"
   },
   {  
      "Install Time":"2016-09-06 20:14:12"
   },
   {  
      "Event Name":"install"
   },
(etc...) //Not part of JSON, just cutting it short
]
Which is great but still won't map to my entities 
解决方案
It looks like you're creating a new JSON object for each KVP rather than grouping the KVP's into a single object. Move the writer.WriteStartObject(); and writer.EndObject(); to outside of the loop and you should end up with a nicely formed JSON Object.
   writer.WriteStartObject();

   foreach (var item in list)
    {

        writer.WritePropertyName(item.Key);
        writer.WriteValue(item.Value);

    }

    writer.WriteEndObject();
    writer.WriteEndArray();
You need to take those Start/End Objects to outside the For loop.

So you should get this instead...
[  
   {  
      "Attributed Touch Time":"2016-09-06 20:11:50"
      "Install Time":"2016-09-06 20:14:12"
      "Event Name":"install"
   },
]


                        
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