WCF OData 服务和 EF 6 问题 - 无法使用 Odata 服务公开实体

Question

我正在使用带有 .NET 框架 4.5.1 和 EF 6.1 的 WCF 数据服务 (Odata)。我使用代码优先的方法来创建 EF 模型。当我将此 EF 模型 (AddProjectModel.cs) 引用到 WCF OData 服务 (WcfDataService1.svc) 时，它会引发以下错误：

错误：

服务器在处理请求时遇到错误。异常消息是“在数据上下文类型“AddProjectModel”上，有一个顶级 IQueryable 属性“资产”，其元素类型不是实体类型。确保 IQueryable 属性是实体类型或在数据上下文类型上指定 IgnoreProperties 属性以忽略此属性。有关更多详细信息，请参阅服务器日志。异常堆栈跟踪是：

在 System.Data.Services.Providers.ReflectionServiceProvider.PopulateMetadata(ProviderMetadataCacheItem metadataCacheItem) 在 System.Data.Services.Providers.BaseServiceProvider.LoadMetadata(Boolean skipServiceOperations) 在 System.Data.Services.DataService1.CreateInternalProvider(Object dataSourceInstance) at System.Data.Services.DataService1.CreateMetadataAndQueryProviders( IDataServiceMetadataProvider& metadataProviderInstance, IDataServiceQueryProvider& queryProviderInstance, Object& dataSourceInstance, Boolean& isInternallyCreatedProvider) 在 System.Data.Services.DataService1.CreateProvider() at System.Data.Services.DataService1.HandleRequest() 在 System.Data.Services.DataService`1.ProcessRequestForMessage(Stream messageBody) 在 SyncInvokeProcessRequestForMessage(Object , Object [] , Object[] ) 在 System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc) 在 System.ServiceModel 的 System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs) .Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc) 在 System.Service Model.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc) 在 System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc) 在 System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc) 在 System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3( MessageRpc& rpc) 在 System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc) 在 System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc) 在 System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc) 在 System.ServiceModel。 Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)

这是我的 WCF 数据服务：WcfDataService1.svc

namespace AddProjectService
{
 public class WcfDataService1 : DataService<AddProjectModel>
 {
    // This method is called only once to initialize service-wide policies.
    public static void InitializeService(DataServiceConfiguration config)
    {
        // TODO: set rules to indicate which entity sets and service operations are visible,
         updatable, etc.
        // Examples:
        config.SetEntitySetAccessRule("*", EntitySetRights.AllRead);
        config.SetServiceOperationAccessRule("*", ServiceOperationRights.All);
        config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V3;
    }
 }
}

我的代码优先模型：AddProjectModel.cs

 public partial class AddProjectModel : DbContext
 {
  public AddProjectModel()
    : base("name=AddProjectModel")
  {
  }

  public virtual DbSet<Asset> Assets { get; set; }
  public virtual DbSet<Project> Projects { get; set; }

  protected override void OnModelCreating(DbModelBuilder modelBuilder)
  {
    modelBuilder.Configurations.Add(new AssetMap());
    modelBuilder.Configurations.Add(new ProjectMap());   
  }         
 }  

 public class AssetMap : EntityTypeConfiguration<Asset>
 {
  public AssetMap()
  {
  this.Property(a => a.AssetId).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);      
  this.HasMany(a => a.Projects).WithRequired(p => p.Asset).HasForeignKey(p => p.AssetId);

  //table  & column mappings
  this.ToTable("TBLASSET");
  this.Property(a => a.AssetId).HasColumnName("ASSETID");
  this.Property(a => a.AssetLevelId).HasColumnName("ASSETLEVELID");
  this.Property(a => a.AssetNumber).HasColumnName("ASSETNUMBER");
  this.Property(a => a.Name).HasColumnName("NAME");
  this.Property(a => a.AssetTypeId).HasColumnName("ASSETTYPEID");      
 }
}  

public class ProjectMap : EntityTypeConfiguration<Project>
{
  public ProjectMap()
  {
   this.Property(p => p.ProjectId).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
   this.HasMany(p => p.SchedulePhases).WithRequired(sp => sp.Project).HasForeignKey(sp => 
   sp.ProjectId); 

  //table & column mappings
  this.ToTable("TBLPROJECT");
  this.Property(p => p.ProjectId).HasColumnName("PROJECTID");
  this.Property(p => p.AssetId).HasColumnName("ASSETID");
  this.Property(p => p.CapitalCategoryId).HasColumnName("CAPITALCATEGORYID");
  this.Property(p => p.Comments).HasColumnName("COMMENTS");
  this.Property(p => p.DesignationId).HasColumnName("DESIGNATIONID");
  this.Property(p => p.DispositionId).HasColumnName("DISPOSITIONID");
  this.Property(p => p.FMSNumber).HasColumnName("FMSNUMBER");
  this.Property(p => p.FundingSourceId).HasColumnName("FUNDINGSOURCEID");
  this.Property(p => p.ImplementerId).HasColumnName("IMPLEMENTERID");
  this.Property(p => p.IsApproved).HasColumnName("ISAPPROVED");
  this.Property(p => p.IsDeferred).HasColumnName("ISDEFERRED");
  this.Property(p => p.IsLongTermLease).HasColumnName("ISLONGTERMLEASE");
  this.Property(p => p.IsRollover).HasColumnName("ISROLLOVER");
  this.Property(p => p.IsSidewalkBridge).HasColumnName("ISSIDEWALKBRIDGE");
  this.Property(p => p.JobDescription).HasColumnName("JOBDESCRIPTION");
  this.Property(p => p.JobType).HasColumnName("JOBTYPE");
  this.Property(p => p.OrganizationId).HasColumnName("ORGANIZATIONID");
  this.Property(p => p.ProgramCategoryId).HasColumnName("PROGRAMCATEGORYID");
  this.Property(p => p.DsfId).HasColumnName("DSFID");
  this.Property(p => p.StatusId).HasColumnName("STATUSID");

  this.Map<DomainObjectModel.ObjectModel.Project.ProjectCIP>(m => m.Requires("PROJECTTYPEID").HasValue(15))
      .Map<DomainObjectModel.ObjectModel.Project.ProjectCapacity>(m => m.Requires("PROJECTTYPEID").HasValue(2));
 }
}

资产类别：

public class Asset
{
 public Asset()
 {
   Projects = new HashSet<Project>();      
 }

 [Key]
 public decimal AssetId { get; set; }

 [StringLength(20)]
 public string AssetNumber { get; set; }

 [StringLength(100)]
 public string Name { get; set; }

 public decimal? AssetLevelId { get; set; }

 public decimal? AssetTypeId { get; set; }

 public virtual ICollection<Project> Projects { get; set; }    
}

项目类：

public class Project
{
 public Project()
 {      
 } 

 [Key]
 public decimal ProjectId { get; set; }

 public decimal AssetId { get; set; }

 public decimal CapitalCategoryId { get; set; }

 //public decimal ProjectTypeId { get; set; }

 public decimal ProgramCategoryId { get; set; }   

 [StringLength(1024)]
 public string Comments { get; set; }

 public decimal ImplementerId { get; set; }

 public decimal StatusId { get; set; }

 public decimal DsfId { get; set; }

 [StringLength(20)]
 public string FMSNumber { get; set; }

 [StringLength(1024)]
 public string JobDescription { get; set; }

 [StringLength(2)]
 public string JobType { get; set; }

 public decimal OrganizationId { get; set; }

 [Required][StringLength(1)]
 public string IsRollover { get; set; }

 [Required][StringLength(1)]
 public string IsDeferred { get; set; }

 [Required][StringLength(1)]
 public string IsApproved { get; set; }

 [StringLength(1)]
 public string IsSidewalkBridge { get; set; }

 public decimal FundingSourceId { get; set; }

 public decimal? DesignationId { get; set; }

 public decimal? DispositionId { get; set; }

 [Required][StringLength(1)]
 public string IsLongTermLease { get; set; }

 public virtual Asset Asset { get; set; }   
}

我不知道如何解决这个问题。你能告诉我我在这里缺少什么吗？

我正在使用 oracle 数据库，我们最近从 devart 购买了 dotConnect for oracle 的许可证。

谢谢，

---

你好，

我已通过在每个 POCO 类上设置带有主键的 [DataServiceKey] 属性来解决此错误。请参考：http://blog.marcgravell.com/2008/12/astoria-and-linq-to-sql-getting-started.html。

现在我可以通过 Odata 服务公开实体，但是当我尝试通过键入 URL（例如 .../WcfDataService1.svc/Assets）来访问实体集合时，它会引发以下错误：

错误：

 <?xml version="1.0" encoding="utf-8" ?> 
 <m:error xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
   <m:code /> 
   <m:message xml:lang="en-US">An error occurred while processing this request.</m:message> 
   <m:innererror>
     <m:message>Operation could destabilize the runtime.</m:message> 
     <m:type>System.Security.VerificationException</m:type> 
     <m:stacktrace>at queryable_reader(Object ) at   System.Data.Services.Providers.ReflectionServiceProvider.GetQueryRootForResourceSet(ResourceSet container) at System.Data.Services.Providers.ReflectionDataServiceProvider.GetQueryRootForResourceSet(ResourceSet resourceSet) at System.Data.Services.Providers.DataServiceProviderWrapper.GetQueryRootForResourceSet(ResourceSetWrapper resourceSet) at System.Data.Services.RequestUriProcessor.ComposeExpressionForEntitySet(SegmentInfo segment, IDataService service, Boolean isLastSegment, Boolean checkRights) at System.Data.Services.RequestUriProcessor.ComposeExpressionForSegments(IList`1 segments, IDataService service, Boolean isCrossReferencingUri) at System.Data.Services.RequestUriProcessor.ProcessRequestUri(Uri absoluteRequestUri, IDataService service, Boolean internalQuery) at System.Data.Services.DataService`1.ProcessIncomingRequestUri() at System.Data.Services.DataService`1.HandleRequest()</m:stacktrace> 
  </m:innererror>
 </m:error>

我该如何解决这个问题？

谢谢，

Answer 1

要将 WCF DataService 与 EF6 一起使用，还需要做一些额外的工作。详情请查看以下两篇博文：

Using WCF Data Services 5.6.0 with Entity Framework 6+

WCF Data Services Entity Framework Provider is updated with WCF Data Service 5.6.2

一般来说，您需要以下两个步骤：

1. 按照该页面上的指南安装最新的 Nuget 包 Microsoft.OData.EntityFrameworkProvider；

2. 将 DataService 替换为 EntityFrameworkDataService，例如在您的 WcfDataService1.svc 中：

   公共类 WcfDataService1：EntityFrameworkDataService