Question

我正在尝试创建Web API模型绑定器，它将绑定由javascript框架的网格组件发送的URL参数。 Grid发送URL参数，指示标准页面，pageSize和JSON格式的分类器，过滤器和分组器。 URL字符串如下所示：

http://localhost/api/inventory?page=1&start=0&limit=10sort=[{"property":"partName","direction":"desc"},{"property":"partStatus","direction":"asc"}]&group=[{"property":"count","direction":"asc"}]

有问题的模型是Inventory，它具有简单的Count（int）属性和引用，Part（Part）peoperty（其中包含Name，Status）。视图模型/ dto被展平（InventoryViewModel .Count，.PartName，.PartStatus等等）我使用Dynamic Expression Api然后查询域模型，将结果映射到视图模型并将其作为JSON发回。在模型绑定期间，我需要通过检查正在使用的模型和视图模型来构建表达式。

为了保持模型绑定器的可重用性，如何传递/指定模型并查看正在使用的模型类型？ 我需要这个来构建有效的排序，过滤和分组表达式注意：我不想将这些作为网格url参数的一部分传递！

我的一个想法是使StoreRequest成为通用（例如StoreRequest），但我不确定模型绑定器是否或如何工作。

示例API控制器

// 1. model binder is used to transform URL params into StoreRequest. Is there a way to "pass" types of model & view model to it?
    public HttpResponseMessage Get(StoreRequest storeRequest)
    {
            int total;
            // 2. domain entites are then queried using StoreRequest properties and Dynamic Expression API (e.g. "Order By Part.Name DESC, Part.Status ASC")
            var inventoryItems = _inventoryService.GetAll(storeRequest.Page, out total, storeRequest.PageSize, storeRequest.SortExpression); 
            // 3. model is then mapped to view model/dto
            var inventoryDto = _mapper.MapToDto(inventoryItems);
            // 4. response is created and view model is wrapped into grid friendly JSON
            var response = Request.CreateResponse(HttpStatusCode.OK, inventoryDto.ToGridResult(total));
            response.Content.Headers.Expires = DateTimeOffset.UtcNow.AddMinutes(5);
            return response;
    }

StoreRequestModelBinder

public class StoreRequestModelBinder : IModelBinder
{
    private static readonly ILog Logger = LogManager.GetCurrentClassLogger();

    public bool BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
    {
        Logger.Debug(m => m("Testing model binder for type: {0}", bindingContext.ModelType));
        if (bindingContext.ModelType != typeof(StoreRequest))
        {
            return false;
        }
        var storeRequest = new StoreRequest();
        // ----------------------------------------------------------------
        int page;
        if (TryGetValue(bindingContext, StoreRequest.PageParameter, out page))
        {
            storeRequest.Page = page;
        }
        // ----------------------------------------------------------------
        int pageSize;
        if (TryGetValue(bindingContext, StoreRequest.PageSizeParameter, out pageSize))
        {
            storeRequest.PageSize = pageSize;
        }
        // ----------------------------------------------------------------
        string sort;
        if (TryGetValue(bindingContext, StoreRequest.SortParameter, out sort))
        {
            try
            {
                storeRequest.Sorters = JsonConvert.DeserializeObject<List<Sorter>>(sort);
                // TODO: build sort expression using model and viewModel types
            } 
            catch(Exception e)
            {
               Logger.Warn(m=>m("Unable to parse sort parameter: \"{0}\"", sort), e);
            }
        }
        // ----------------------------------------------------------------
        bindingContext.Model = storeRequest;
        return true;
    }

    private bool TryGetValue<T>(ModelBindingContext bindingContext, string key, out T result)
    {
        var valueProviderResult = bindingContext.ValueProvider.GetValue(key);
        if (valueProviderResult == null)
        {
            result = default(T);
            return false;
        }
        result = (T)valueProviderResult.ConvertTo(typeof(T));
        return true;
    }
}

Answer 1

只需更改控制器签名，如

public HttpResponseMessage Get([ModelBinder(typeof(StoreRequestModelBinder)]StoreRequest storeRequest)

此致

将参数传递给Web API模型绑定器

1 个答案: