用Json.NET填充不可序列化的对象 [英] Populating non-serializable object with Json.NET

问题描述

在测试中，我想从JSON字符串填充对象(视图模型).例如，目标对象具有以下属性:

In a test I want to populate an object (a view model) from a JSON string. For example, the target object has this property:

public string Query { get; set; }

所以我希望能够做到这一点:

So I want to be able to do this:

var target = ...;
JsonConvert.PopulateObject(target, "{ 'Query': 'test' }");

但是，未设置Query属性.通过代码调试，似乎会忽略target上的属性，因为成员序列化是可选的.由于目标类不是数据协定，并且不会以这种方式在单元测试之外进行填充，因此我无法通过属性将其选择为成员序列化.

However, the Query property is not being set. Debugging through the code, it appears that properties on target are ignored because member serialization is opt-in. Since the target class is not a data contract and is not populated in this way outside of unit tests, I cannot opt it into member serialization via attributes.

我找不到从外部修改成员序列化的方法.我希望通过PopulateObject进行设置的超载可以使我这样做，但是我看不到有任何办法.

I can't find a way to modify the member serialization from the outside. I was hoping the overload of PopulateObject taking settings would allow me to do so, but I don't see any way to do so.

即使不是数据合同，如何确保PopulateObject在目标上设置属性?

How can I ensure PopulateObject sets properties on my target even though it isn't a data contract?

推荐答案

您可以创建

You can create a ContractResolver that interprets all classes as opt-out rather than opt-in:

public class OptOutContractResolver : DefaultContractResolver
{
    protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
    {
        return base.CreateProperties(type, MemberSerialization.OptOut);
    }
}

然后像这样使用它:

[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
//[DataContract] -- also works.
public class TestClass
{
    public string Query { get; set; } // Not serialized by default since this class has opt-in serialization.

    public static void Test()
    {
        var test = new TestClass { Query = "foo bar" };
        var json = JsonConvert.SerializeObject(test, Formatting.Indented);
        Debug.Assert(!json.Contains("foo bar")); // Assert the initial value was not serialized -- no assert.
        Debug.WriteLine(json);

        var settings = new JsonSerializerSettings { ContractResolver = new OptOutContractResolver() };
        JsonConvert.PopulateObject("{ 'Query': 'test' }", test, settings);
        Debug.Assert(test.Query == "test"); // Assert the value was populated -- no assert.

        Debug.WriteLine(JsonConvert.SerializeObject(test, Formatting.Indented, settings));
    }
}

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