Question

我需要帮助找出如何将表值函数公开为Web Api 2 OData v4服务中设置的实体的属性。

我的简化架构有三个表，Structures，Locations和LocationLinks。结构包含带有节点（Locatons）和边（LocationLinks）的图形。我使用Entity Framework 6数据库第一个模型访问。

Simplified Schema

  Structure:
      ID

  Locations:
      ID
      ParentID -> Structure

  LocationLinks
      A -> Location
      B -> Location

目标是以与访问结构位置相同的方式访问LocationLinks的结构集合。即要求结构＃180的图表：

http://.../OData/Structures(180)/LocationLinks
http://.../OData/Structures(180)/Locations

“位置”查询会自动生效，但我无法弄清楚如何添加正确的路线以启用LocationLinks查询。认为它会使我的任务更容易，我已经将一个表值函数添加到我的SQL服务器。该函数存在于我的EF模型中，并返回LocationLink实体的集合：

StructureLocationLinks(@StructureID) -> LocationLinks

不幸的是，无论我尝试什么，我似乎无法使Structure（180）\ LocationLinks URL功能正常。这是我最近的尝试：

StructuresController.cs片段：

        // GET: odata/Structures(5)/Locations
        [EnableQuery]
        public IQueryable<Location> GetLocations([FromODataUri] long key)
        {
            return db.Structures.Where(m => m.ID == key).SelectMany(m => m.Locations);
        }

        // GET: odata/Structures(5)/LocationLinks
        [EnableQuery]        
        //[System.Web.OData.Routing.ODataRoute("Structures({key})")]
        public IQueryable<LocationLink> GetLocationLinks([FromODataUri] long key)
        {
            return db.StructureLocationLinks(key);
        }

WebApi.cs片段：

public static void Register(HttpConfiguration config)
        {
            // Web API configuration and services
            var json = GlobalConfiguration.Configuration.Formatters.JsonFormatter;
            json.UseDataContractJsonSerializer = true;
            //json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.All;

            //var cors = new System.Web.Http.Cors.EnableCorsAttribute("*", "*", "*");
            //config.EnableCors(cors);

            // Web API routes 
            config.MapHttpAttributeRoutes();

            ODataConventionModelBuilder builder = GetModel();

            config.MapODataServiceRoute(routeName: "odata",
                routePrefix: null,
                model: builder.GetEdmModel());

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

    public static ODataConventionModelBuilder GetModel()
        {
            ODataConventionModelBuilder builder = new ODataConventionModelBuilder();

            builder.Namespace = typeof(Structure).Namespace;

            AddLocationLinks(builder);
            AddStructures(builder);
            builder.EntitySet<Location>("Locations");

            return builder;
        }

        public static void AddStructures(ODataModelBuilder builder)
        {
            var structSetconfig = builder.EntitySet<Structure>("Structures");
            var structConfig = structSetconfig.EntityType;

            var functionConfig = structConfig.Collection.Function("StructureLocationLinks");
            functionConfig.Parameter<long>("StructureID");
            functionConfig.Returns<LocationLink>();
        }


        public static void AddLocationLinks(ODataModelBuilder builder)
        {
            var type = builder.EntityType<LocationLink>();
            type.HasKey(sl => sl.A);
            type.HasKey(sl => sl.B);
            builder.EntitySet<LocationLink>("LocationLinks");
        }

我收到的错误是：

{ “错误”：{ “code”：“”，“message”：“找不到与请求URI匹配的HTTP资源。 'http://.../OData/Structures(180)/LocationLinks' “” innererror“：{ “message”：“找不到使用模板为OData路径选择操作的路由约定 '〜/ EntitySet的/关键码/悬而未决' “” 类型 “：””， “堆栈跟踪”： “” }}

基于某些搜索，我尝试将ODataRoute属性添加到控制器：

// GET: odata/Structures(5)/LocationLinks
[EnableQuery]        
[System.Web.OData.Routing.ODataRoute("Structures({key})/LocationLinks")]
public IQueryable<LocationLink> GetLocationLinks([FromODataUri] long key)
{
    return db.StructureLocationLinks(key);
}

导致此错误：

动作上的路径模板'Structures（{key}）/ LocationLinks' 控制器'Structures'中的'GetLocationLinks'不是有效的OData 路径模板。找到了一个未解决的路径段“LocationLinks” OData路径模板'Structures（{key}）/ LocationLinks'。

如何从Structures集合中公开LocationLinks？谢谢你的时间。

修改

我找到这个问题后设法让这个工作： Adding a custom query backed Navigation Property to ODataConventionModelBuilder

我必须在我的ODataConventionBuilder对象上调用.GetEdmModel，然后使用此函数将导航属性添加到模型中：

private static Microsoft.OData.Edm.IEdmModel AddStructureLocationLinks(IEdmModel edmModel)
        { 

            var structures = edmModel.EntityContainer.FindEntitySet("Structures") as EdmEntitySet;
            var locationLinks = edmModel.EntityContainer.FindEntitySet("LocationLinks") as EdmEntitySet;
            var structType = structures.EntityType() as EdmEntityType;
            var locLinksType = locationLinks.EntityType() as EdmEntityType;

            var structLocLinksProperty = new EdmNavigationPropertyInfo();
            structLocLinksProperty.TargetMultiplicity = Microsoft.OData.Edm.EdmMultiplicity.Many;
            structLocLinksProperty.Target = locLinksType;
            structLocLinksProperty.ContainsTarget = true; 
            structLocLinksProperty.OnDelete = Microsoft.OData.Edm.EdmOnDeleteAction.None;
            structLocLinksProperty.Name = "LocationLinks";

            var navigationProperty = structType.AddUnidirectionalNavigation(structLocLinksProperty);
            structures.AddNavigationTarget(navigationProperty, locationLinks);

            return edmModel; 
        }

我现在遇到的问题是我在查询中访问导航属性的能力有限。例如，此链接有效：

http://.../OData/Structures(180)/Children?$expand=Locations

虽然这不是。

http://.../OData/Structures(180)/Children?$expand=LocationLinks

返回的错误是

{“error”：{ “code”：“”，“message”：“发生错误。”，“innererror”： { “message”：“实例属性'LocationLinks'未定义类型'ConnectomeDataModel.Structure'”， “type”：“System.ArgumentException”，“stacktrace”：“at System.Linq.Expressions.Expression.Property（Expression expression， String propertyName）\ r \ n at System.Web.OData.Query.Expressions.SelectExpandBinder.CreatePropertyValueExpressionWithFilter（IEdmEntityType elementType，IEdmProperty属性，Expression source，FilterClause filterClause）\ r \ n at System.Web.OData.Query.Expressions.SelectExpandBinder.BuildPropertyContainer（IEdmEntityType elementType，Expression source，Dictionary 2 propertiesToExpand, ISet 1 propertiesToInclude，ISet 1 autoSelectedProperties, Boolean isSelectingOpenTypeSegments)\r\n at System.Web.OData.Query.Expressions.SelectExpandBinder.ProjectElement(Expression source, SelectExpandClause selectExpandClause, IEdmEntityType entityType)\r\n at System.Web.OData.Query.Expressions.SelectExpandBinder.Bind(IQueryable queryable)\r\n at System.Web.OData.Query.ODataQueryOptions.ApplySelectExpand[T](T entity, ODataQuerySettings querySettings)\r\n at System.Web.OData.Query.ODataQueryOptions.ApplyTo(IQueryable query, ODataQuerySettings querySettings)\r\n at System.Web.OData.EnableQueryAttribute.ExecuteQuery(Object response, HttpRequestMessage request, HttpActionDescriptor actionDescriptor)\r\n at System.Web.OData.EnableQueryAttribute.OnActionExecuted(HttpActionExecutedContext actionExecutedContext)\r\n at System.Web.Http.Filters.ActionFilterAttribute.OnActionExecutedAsync(HttpActionExecutedContext actionExecutedContext, CancellationToken cancellationToken)\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Filters.ActionFilterAttribute.<CallOnActionExecutedAsync>d__5.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Filters.ActionFilterAttribute.<ExecuteActionFilterAsyncCore>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter 1.GetResult（）\ r \ n at System.Web.Http.Controllers.ActionFilterResult.d__2.MoveNext（个）\ r \ n --- 从抛出异常的先前位置开始的堆栈跟踪结束 --- \ r \ n在System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）\ r \ n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务）\ r \ n at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult（）\ r \ n at System.Web.Http.Dispatcher.HttpControllerDispatcher.d__1.MoveNext（）” }}

Answer 1

Xycor

如您所述，LocationLinks应与Locations的{{1}}相同。所以，我认为你为控制器和行动所做的是正确的。我根据您的描述进行了测试，似乎Web API OData可以按惯例路由Structure。

让我展示我的元数据文档，请忽略命名空间并与您的名称空间进行比较，让我知道任何不同之处。感谢。

GetLocationLinks

如何将表值函数公开为Web Api 2 OData v4服务中实体集的属性？

1 个答案: