如何在WebAPI中将可变数量的参数传递给GET

config.Routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

public HttpResponseMessage Get( string where_name, 
                                IndexFieldsModel index_fields = null )

public class IndexFieldsModel
{
    public List<IndexFieldModel> Fields { get; set; }
}

public class IndexFieldModel
{
    public string Name { get; set; }
    public string Value { get; set; }
}
config.Routes.MapHttpRoute(
    name: "DefaultA