从 .NET v4.7.2 切换到 .NET 标准 v2.0 时，在 DefaultContractResolver 中找不到 IgnoreSerializableAttribute

Question

I'm in the process of migrating one of our libraries from .NET v4.7.2 to .NET Standard v2.0.

This code compiles when using .NET v4.7.2

var resolver = new DefaultContractResolver
{
    IgnoreSerializableAttribute = true,
    NamingStrategy = new CamelCaseNamingStrategy(true, true),
};

but when using .NET Standard it does not. Apparently IgnoreSerializableAttribute is not part of DefaultContractResolver in v9.01 of Newtonsoft.Json when using .NET Standard.

I'm using v9.01 of Newtonsoft.Json as we're still using v1.0 Azure functions and they only work with v9.01.

Can anyone explain what's happening and why there's a difference between Newtonsoft.Json v9.01 in .NET v4.7.2 and .NET Standard v2.0?

Answer 1

You do not need to set IgnoreSerializableAttribute to true because it is true by default. This can be seen in the reference source for DefaultContractResolver :

 public DefaultContractResolver() { #if HAVE_BINARY_SERIALIZATION IgnoreSerializableAttribute = true; #endif #pragma warning disable 618 DefaultMembersSearchFlags = BindingFlags.Instance | BindingFlags.Public; #pragma warning restore 618 _contractCache = new ThreadSafeStore<Type, JsonContract>(CreateContract); }

Thus on all versions of Json.NET, the following code will create a contract resolver that ignores the [Serializable] attribute:

var resolver = new DefaultContractResolver
{
    NamingStrategy = new CamelCaseNamingStrategy(true, true),
};

To answer your specific question as to why IgnoreSerializableAttribute is not present in Json.NET v9.0.1 when targeting .NET Standard 2.0 , it is because v9.0.1 actually only targets .NET Standard 1.0, and Microsoft's System.SerializableAttribute did not exist in .NET Standard 1.0. If I recall, MSFT introduced it into .NET Standard 2.0 as part of the partial back-port of binary serialization (now deprecated ). When Json.NET added support for .NET Standard 2.0 in release 11 , support for IgnoreSerializableAttribute got included.