.net 4.5 控制器：参数多态性和自定义 Json 反序列化

Question

我有一个 API，其中有一个同步控制器。 这个控制器只有一个动作函数：ActionRequest

public IHttpActionResult ActionRequest([FromBody]ActionRequestDto model)
{
    //EXAMPLE OF PASSING AND ARTICLE IN OBJECT THREW POST METHOD
    ArticleDto article = null;
    if(model.ActionType == "Article"){
        article = (ArticleDto)model.Object; //Problem ==> model.Object looses all articles information and cannot be cast to article
    }
}

这个功能应该像路由器一样工作。它读取操作请求并调用相应的存储库。

ActionRequest 对象有这样的结构：

public class ActionRequestDto
{
    public string ActionType { get; set; }
    public string ObjectType { get; set; }
    public bool Transmited { get; set; } = false;
    public DateTime CreationDate { get; set; }
    public int RequestNumber { get; set; }
    public string Reference { get; set; }
    public BaseDto Object { get; set; }// this is where the data is passed.
                   //it can be any type extending from BaseDto (ArticleDto, CustomerDto... )
}

我需要获取最终对象，而不仅仅是控制器中的基础对象，以便将其传递给服务。

如何更改反序列化行为，但仅针对此操作或至少针对此控制器？

Answer 1

大家早上好。

我受到这个问题的启发：Automatically deserialize to string-like class in Web.API controller

这就是我所做的。

1. 创建自定义 Json 转换器类

   public class BaseDtoJsonConvertor : JsonConverter
   {
   
   public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
   {
       var actionRequestDto = (ActionRequestDto)value;
   
       writer.WriteStartObject();
       writer.WritePropertyName("ActionRequestDto");
       serializer.Serialize(writer, actionRequestDto.ToString());
       writer.WriteEndObject();
   }
   
   public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
   {
       // Variables to be set along with sensing variables
       ActionRequestDto actionRequestDto = new ActionRequestDto();
       // Read the properties
       while (reader.Read())
       {
           if (reader.TokenType != JsonToken.PropertyName)
           {
               break;
           }
           var propertyName = (string)reader.Value;
           if (!reader.Read())
           {
               continue;
           }
           // Set the group
           if (propertyName.Equals("object", StringComparison.OrdinalIgnoreCase))
           {
               actionRequestDto.Object = JsonSerializerBaseObjectFactory.DeserializeObject(actionRequestDto.ObjectType, reader, serializer);
           }
           if (propertyName.Equals("ActionType", StringComparison.OrdinalIgnoreCase))
           {
               actionRequestDto.ActionType = serializer.Deserialize<string>(reader);
           }
           if (propertyName.Equals("ObjectType", StringComparison.OrdinalIgnoreCase))
           {
               actionRequestDto.ObjectType = serializer.Deserialize<string>(reader);
           }
           if (propertyName.Equals("Transmited", StringComparison.OrdinalIgnoreCase))
           {
               actionRequestDto.Transmited = serializer.Deserialize<bool>(reader);
           }
           if (propertyName.Equals("CreationDate", StringComparison.OrdinalIgnoreCase))
           {
               actionRequestDto.CreationDate = serializer.Deserialize<DateTime>(reader);
           }
           if (propertyName.Equals("RequestNumber", StringComparison.OrdinalIgnoreCase))
           {
               actionRequestDto.RequestNumber = serializer.Deserialize<int>(reader);
           }
           if (propertyName.Equals("Reference", StringComparison.OrdinalIgnoreCase))
           {
               actionRequestDto.Reference = serializer.Deserialize<string>(reader);
           }
       }
       return actionRequestDto;
   }
   
   public override bool CanConvert(Type objectType)
   {
       return objectType == typeof(ActionRequestDto);
   }
   }
   

2. 创建一个工厂类以返回所需的对象类型

   class JsonSerializerBaseObjectFactory
   {
   
   
   public enum Types
   {
       Article,
       Basket,
       Customer,
       WishList,
       User,
       Tarif,
       Store,
       Stock,
       ShippingTaxe,
       Seller,
       SalesDocument,
       Promotion,
       Payment,
       InventoryTransaction,
       Inventory,
       Family,
       Etablissement,
       Dimension,
       Depot,
       CreditCard,
       Country,
       Commande,
       Category,
       Cashier,
       AvailableQuantity,
       ArticleRequest
   };
   public static BaseDto DeserializeObject(string type, JsonReader reader, JsonSerializer serializer)
   {
       Types typeRes;
       if (Enum.TryParse(type, out typeRes))
       {
           switch (typeRes)
           {
               case Types.Article:
                   return serializer.Deserialize<ArticleDto>(reader);
               case Types.Basket:
                   return serializer.Deserialize<BasketDto>(reader);
               case Types.Customer:
                   return serializer.Deserialize<CustomerDto>(reader);
               default:
                   return serializer.Deserialize<BaseDto>(reader);
   
           }
       }
       return serializer.Deserialize<BaseDto>(reader);
   }
   
   }
   

3. 最后在 StartUp 类中取消自定义 JsonConvertor

       var config = GlobalConfiguration.Configuration;
       var jsonSettings = config.Formatters.JsonFormatter.SerializerSettings;
       jsonSettings.Converters.Add(new BaseDtoJsonConvertor());
   

仅此而已。任何时候我收到一个 Actionrequest Object 类型，它都会被反序列化并抛出我的自定义 jsonConvertor。