8

I'm trying to bind a controller action to an interface but still maintain the default binding behavior.

public class CoolClass : ISomeInterface
{
    public DoSomething {get;set;} // ISomeInterface
}

public class DosomethingController : ApiController
{
    public HttpResponseMessage Post(ISomeInterface model)
    {
        // do something with model which should be an instance of CoolClass
    }
}

The consumer of my service knows nothing of CoolClass so having them add "$type" to the Json they are passing would be a hack in my opinion. I'd like to be able to handle it in the service. If I specify CoolClass as the action parameter it works fine.

EDIT: So I found a partial solution to my question here Dependency injection for ASP.NET Web API action method parameters but there is a follow up issue. That solution does not resolve interface properties. See my example below.

IConcreteClass will be resolved, but ISubtype will not.

public class SubConcreteClass : ISubtype
{
    // properties
}

public class ConcreteClass : IConcreteClass
{
    public ISubtype Subtype {get;set;}
}

Once the media formatter sees that is can resolve the type in IConcreteClass, it then reads the entire stream. So I'm guessing there is no chance to resolve interface members.

4

2 回答 2

13

因此，如果这可以帮助其他任何人，我会继续发布我提出的解决方案。

正如我上面提到的，action方法的接口参数可以使用DI来解析。但是该对象的接口成员需要以不同的方式处理。

我创建了两种类型的 Json 转换器，一个实体类型和一个集合类型，来装饰接口属性。

这是一个需要作为操作接口参数解析的类。

public class CreateEnvelopeModel : ICreateEnvelopeCommand
{
    [JsonConverter(typeof(EntityModelConverter<CreateEmailModel, ICreateEmailCommand>))]
    public ICreateEmailCommand Email { get; set; }
    [JsonConverter(typeof(CollectionEntityConverter<CreateFormModel, ICreateFormCommand>))]
    public IList<ICreateFormCommand> Forms { get; set; }
}

这是控制器操作方法

public HttpResponseMessage PostEnvelope(ICreateEnvelopeCommand model)
{
    // do stuff
}

这是 2 个 json 转换器

public class EntityModelConverter<T, Tt> : JsonConverter where T : Tt
{
    public override bool CanConvert(Type objectType)
    {
        return (objectType == typeof(Tt));
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        return serializer.Deserialize<T>(reader);
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        serializer.Serialize(writer, value, typeof(T));
    }
}

public class CollectionEntityConverter<T, Tt> : JsonConverter where T : Tt
{
    public override bool CanConvert(Type objectType)
    {
        return (objectType == typeof(IList<Tt>));
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        IList<Tt> items = serializer.Deserialize<List<T>>(reader).Cast<Tt>().ToList();
        return items;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        serializer.Serialize(writer, value, typeof(IList<T>));
    }
}
于 2013-08-28T14:20:02.043 回答
-1

看这里Model Binders的部分。我认为这是你的情况。

于 2013-08-20T13:35:38.127 回答