Question

Json.NET现在发现,在这种类型的所有领域,无论是公共领域还是私人领域,都有可扩展的Attribute和序列号,忽略了这些特性。

下面的样本代码显示:

Error getting value from CS$<>9__CachedAnonymousMethodDelegate1 on ConsoleApplication1.MyType .

如果我评论了WithLambda的财产,那么序列化就会如期成功。事实上,我取得了以下成果:

Leave [Serializable], leave TotalWithLambda: throws JsonSerializationException
Leave [Serializable], remove TotalWithLambda: serializes "myList" only
Remove [Serializable], leave TotalWithLambda: serializes "myList", "Total", and "TotalWithLambda"
Remove [Serializable], remove TotalWithLambda: serializes "myList" and "Total"

I understand all of these cases except the first one. Why does the combination of [Serializable] and a read-only property with a lambda in it cause this exception?

namespace ConsoleApplication1
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using Newtonsoft.Json;

    class Program
    {
        static void Main(string[] args)
        {
            var foo = new MyType();
            foo.myList = new List<int>() { 0, 1, 2, 3 };

            var returnVal = JsonConvert.SerializeObject(foo);

            Console.WriteLine("Return: " + returnVal.ToString());
            Console.ReadKey();
        }
    }

    [Serializable]
    class MyType
    {
        public IList<int> myList;
        public int Total { get { return this.myList.Sum(); } }
        public int TotalWithLambda { get { return this.myList.Sum(x => x); } }
    }

}

Answer 1

我安装并使用了 JustDecompile ,发现编辑在Mlambda未加工时向该类别增加了一个领域和一个方法:

public class MyType
{
    [CompilerGenerated]
    private static Func<int, int> CS$<>9__CachedAnonymousMethodDelegate1;

    [CompilerGenerated]
    private static int <get_TotalWithLambda>b__0(int x) { ... }

    // ... plus the other class members ...
}

When the class has SerializableAttribute on it, Json.NET tries to serialize the private field, but can t since it s of type Func<int, int>. Removing the SerializableAttribute instructs Json.NET to ignore private fields and so it doesn t cause a problem.

<>Update: Json.NET 4.5 release 3 现在,只有你明确制定<条码>(IgnoreSerializableAttribute=false,或者可以通过添加<条码>加以解决。 JsonObjectAttribute 。

Answer 2

I ve changed IgnoreSerializableAttribute to true by default in release 3 which undoes the breaking change introduced in release 2 - http://json.codeplex.com/releases/view/85975

http://json.codeplex.com/discussions/351981”rel=“nofollow”http://json.codeplex.com/discussions/351981。

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