.NET核心3Web API：[FromBody]如何绑定抽象类属性

public class AbstractModelBinder : IModelBinder
{
    public Task BindModelAsync(ModelBindingContext bindingContext)
    {
        // 获取请求内容
        var json = bindingContext.HttpContext.Request.Body;

        // 将请求内容反序列化为抽象类的实例
        var serializer = new JsonSerializer();
        using (var reader = new StreamReader(json))
        {
            using (var jsonReader = new JsonTextReader(reader))
            {
                var instance = serializer.Deserialize(jsonReader, bindingContext.ModelType);
                bindingContext.Result = ModelBindingResult.Success(instance);
                return Task.CompletedTask;
            }
        }
    }
}

public class MyModel
{
    [ModelBinder(BinderType = typeof(AbstractModelBinder))]  
    public AbstractClass Property { get; set; }
}