RESTier OData 函数返回 EntitySet。 “无法从 OData 路径中找到相关实体集”答案

【问题标题】：RESTier OData Function returning EntitySet. "The related entity set could not be found from the OData path"RESTier OData 函数返回 EntitySet。 “无法从 OData 路径中找到相关实体集”
【发布时间】：2015-10-23 21:06:30
【问题描述】：

在 RESTier OData 上添加了一个功能

var ambilLocationsByMarketId = new EdmAction(ns, "AmbilLocationsByMarketId", location.GetEdmTypeReference(true), false, null);
model.AddElement(ambilLocationsByMarketId);
var entityContainer = (EdmEntityContainer)model.EntityContainer;
entityContainer.AddActionImport("AmbilLocationsByMarketId", ambilLocationsByMarketId);

在我的 DomainController 中实现了自定义功能

[HttpGet]
[EnableQuery]
[ODataRoute("AmbilLocationsByMarketId")]
public IHttpActionResult AmbilLocationsByMarketId()
{
    var locations = DbContext.Locations.Where(l => l.Name.Contains("Hotel")).Select(l => l);
    return Ok(locations);
}

但我不断得到这个结果作为回报

{
  "error": {
    "code": "",
    "message": "An error has occurred.",
    "innererror": {
      "message": "The 'ObjectContent`1' type failed to serialize the response body for content type 'application/json; odata.metadata=minimal'.",
      "type": "System.InvalidOperationException",
      "stacktrace": "",
      "internalexception": {
        "message": "The related entity set could not be found from the OData path. The related entity set is required to serialize the payload.",
        "type": "System.Runtime.Serialization.SerializationException",
        "stacktrace": "   at System.Web.OData.Formatter.Serialization.ODataFeedSerializer.WriteObject(Object graph, Type type, ODataMessageWriter messageWriter, ODataSerializerContext writeContext)\\\r\\\n   at System.Web.OData.Formatter.ODataMediaTypeFormatter.WriteToStream(Type type, Object value, Stream writeStream, HttpContent content, HttpContentHeaders contentHeaders)\\\r\\\n   at System.Web.OData.Formatter.ODataMediaTypeFormatter.WriteToStreamAsync(Type type, Object value, Stream writeStream, HttpContent content, TransportContext transportContext, 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.Runtime.CompilerServices.TaskAwaiter.GetResult()\\\r\\\n   at System.Web.Http.WebHost.HttpControllerHandler.<WriteBufferedResponseContentAsync>d__1b.MoveNext()"
      }
    }
  }
}

如何在 RESTier 上分配正确的返回 EntitySet 集合？我想返回对象列表/ IQueryable

【问题讨论】：

使用函数的API不是比添加元素更容易吗？类似于： FunctionConfiguration personFn = builder.EntityType().Function("GetFamilyMembers").Returns(); personFn.Parameter("方向");
@MarvinSmit 我们知道这一点。我们正在尝试在 OData 之上使用 RESTier。

标签： asp.net-mvc odata restier

【解决方案1】：

您需要修改两个地方才能使其工作：

1) 声明动作时需要添加collection返回类型。

2) 添加 ActionImport 时需要添加 EdmEntitySetReferenceExpression。

请参阅https://github.com/OData/RESTier/blob/master/test/ODataEndToEndTests/Microsoft.Restier.WebApi.Test.Services.Trippin/Domain/TrippinDomain.cs#L177-L189 获取示例（虽然它是 FunctionImport 但也应适用于 ActionImport）。

【讨论】：