1

当我尝试使用 json.net 将对象转换为 json 时出现错误。

错误：

  Unable to cast object of type 'System.Collections.Generic.List`1[System.Int32]' to type
 'MyNamespace.Domain.Entity'.

要序列化的类：

[Serializable]
public class Business:Entity
    {
        public virtual string TemplateName { get; set; }

        public virtual CalculationBasis CalculationBasis { get; set; }

        public virtual PeriodSelectionType PeriodSelectionType { get; set; }

        public virtual DateTime PeriodEndDate { get; set; }

        public virtual IEnumerable<int> mainKeys { get; set; }
  }

序列化代码：

JsonSerializerSettings settings = new JsonSerializerSettings();
    settings.NullValueHandling = NullValueHandling.Ignore;
    settings.DateFormatHandling = DateFormatHandling.MicrosoftDateFormat;
    var strJson = JsonConvert.SerializeObject( ObjectOfBusiness, settings);

反序列化代码：

JsonConvert.DeserializeObject<Business>(ObjectOfBusiness, settings);

当我有值时，我只会收到此错误IEnumerable<int> mainKeys

注意：mainKeys 是一个List<int>

看起来错误是因为它的父类 "Entity" ，类是这样的：

  [Serializable]
    public abstract class Entity
    {
        public Entity()
        {
        }

        public Entity(int id)
        {
            this.Id = id;
        }

        public virtual int Id { get; set; }

        public override bool Equals(object obj)
        {
            Entity other = (Entity)obj;
            return this.Id == other.Id;
        }

        public override int GetHashCode()
        {
            return this.Id.GetHashCode();
        }
    }

不知道为什么 json.net 试图将 IEnumerable 转换为“实体”类型（它的父类）..

我无法删除实体（父类），因为它在很多地方都被使用过..

请建议。

谢谢

4

2 回答 2

2

终于找到了解决办法。问题是由于方法中的代码不佳override bool Equals(object obj)。正确的代码是：

  public override bool Equals(object obj)
        {
            if (obj is Entity)
            {
                Entity other = (Entity) obj;
                return this.Id == other.Id;
            }
            else
            {
                return false;
            }
        }

http://json.codeplex.com/workitem/16554

于 2013-09-23T05:55:00.527 回答
0

这不是一个真正的答案 - 它是一个“这很好用”：

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
public class Entity { }
public class CalculationBasis { }
public class PeriodSelectionType { }
[Serializable]
public class Business : Entity
{
    public virtual string TemplateName { get; set; }
    public virtual CalculationBasis CalculationBasis { get; set; }
    public virtual PeriodSelectionType PeriodSelectionType { get; set; }
    public virtual DateTime PeriodEndDate { get; set; }
    public virtual IEnumerable<int> mainKeys { get; set; }
}
class program
{
    static void Main()
    {
        JsonSerializerSettings settings = new JsonSerializerSettings();
        settings.NullValueHandling = NullValueHandling.Ignore;
        settings.DateFormatHandling = DateFormatHandling.MicrosoftDateFormat;

        var ObjectOfBusiness = new Business
        {
            TemplateName = "abc",
            CalculationBasis = new CalculationBasis(),
            PeriodSelectionType = new PeriodSelectionType(),
            PeriodEndDate = new DateTime(),
            mainKeys = new int[] { 1, 2, 3, 4, 5 }
        };
        var strJson = JsonConvert.SerializeObject(ObjectOfBusiness, settings);
        //...
        var obj = JsonConvert.DeserializeObject<Business>(strJson, settings);
        // ^^^^ all good
    }
}

所以：如果你能展示一个失败的案例，或者给我们更多的线索继续下去，那就太好了。有关信息，上面的 JSON 是：

{"TemplateName":"abc","CalculationBasis":{},"PeriodSelectionType":{},"PeriodEndDate":"\/Date(-62135596800000)\/","mainKeys":[1,2,3,4,5]}
于 2013-09-20T09:52:13.467 回答