XSD.EXE + JSON.NET - 如何处理xxxSpecified生成的成员？

Question

使用XSD.EXE从XML Schema生成类时，它会生成给定对象的任何基元的xxxSpecified成员：

<xs:complexType name ="Foo">
    <xs:all>
      <xs:element name ="Count" type = "xs:integer"/>
    </xs:all>
</xs:complexType>

....产生：

public class Foo
{
    public int Count { get; set; }
    public bool CountSpecified { get; set; }
}

看来最新版本的JSON.NET可以在反序列化时自动设置这些属性。

string request = "{ Count : 10 }";
var object = JsonConvert.Deserialize<Foo>(request)
Assert.IsTrue(object.Count = 10); // Yup
Assert.IsTrue(object.CountSpecified == true);  //Also yup - JSON.NET works!

但是，当以另一种方式运行时，xxxSpecified属性包含在JSON输出中，这是不正确的，因为它不是模式的一部分。

string request = JsonConvert.Serialize(object); 
//{  
//   Count: 10, 
//   CountSpecified : true    <-- This is incorrect - should not be output 
//}

是否有任何我缺少的设置控制是否输出xxxSpecified属性？我怎么能抑制它？

（注意：这是这里回答的问题的排列：

JSON.NET, XmlSerializer and "Specified" property

...但它涉及创建扩展类，这对我来说是不可能的，因为模式中有数百个类，我无法更改继承层次结构。所以答案是行不通的。寻找另一种方式。）

Answer 1

您可以创建自己的合约解析程序来过滤掉xxxSpecified属性：

public class SkipSpecifiedContractResolver : DefaultContractResolver
{
    // As of 7.0.1, Json.NET suggests using a static instance for "stateless" contract resolvers, for performance reasons.
    // http://www.newtonsoft.com/json/help/html/ContractResolver.htm
    // http://www.newtonsoft.com/json/help/html/M_Newtonsoft_Json_Serialization_DefaultContractResolver__ctor_1.htm
    // "Use the parameterless constructor and cache instances of the contract resolver within your application for optimal performance."
    static SkipSpecifiedContractResolver instance;

    static SkipSpecifiedContractResolver() { instance = new SkipSpecifiedContractResolver(); }

    public static SkipSpecifiedContractResolver Instance { get { return instance; } }

    protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
    {
        var properties = base.CreateProperties(type, memberSerialization);
        ILookup<string, JsonProperty> lookup = null;
        foreach (var property in properties)
        {
            if (property.GetIsSpecified != null && property.SetIsSpecified != null)
            {
                var name = property.UnderlyingName + "Specified";
                lookup = lookup ?? properties.ToLookup(p => p.UnderlyingName);
                var specified = lookup[name]
                    // Possibly also check for [XmlIgnore] being applied.  While not shown in the question, xsd.exe will always
                    // apply [XmlIgnore] to xxxSpecified tracking properties.
                    //.Where(p => p.AttributeProvider.GetAttributes(typeof(System.Xml.Serialization.XmlIgnoreAttribute),true).Any())
                    .SingleOrDefault();
                if (specified != null)
                    specified.Ignored = true;
            }
        }
        return properties;
    }
}

然后使用它像：

var settings = new JsonSerializerSettings { ContractResolver = SkipSpecifiedContractResolver.Instance };
var object = JsonConvert.DeserializeObject<Foo>(request, settings);

如果您想要始终执行此操作，可以在全局JsonConvert.DefaultSettings中设置合约解析程序：

JsonConvert.DefaultSettings = (() =>
{
    return new JsonSerializerSettings { ContractResolver = SkipSpecifiedContractResolver.Instance };
});