WCF OData Service and EF 6 issue - Can't expose entities using Odata Service

Question

I am using WCF Data Service (Odata) with .NET framework 4.5.1 and EF 6.1. I have used code first approach to create EF model. When I reference this EF model (AddProjectModel.cs) to WCF OData Service (WcfDataService1.svc), it throws following error:

Error:

The server encountered an error processing the request. The exception message is 'On data context type 'AddProjectModel', there is a top IQueryable property 'Assets' whose element type is not an entity type. Make sure that the IQueryable property is of entity type or specify the IgnoreProperties attribute on the data context type to ignore this property.'. See server logs for more details. The exception stack trace is:

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

Here is my WCF Data Service: 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;
    }
 }
}

My Code First Model: 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));
 }
}

Asset class:

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; }    
}

Project class:

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; }   
}

I don't know how to resolve this issue. Could you please tell me what I am missing here?

I am using oracle database and we have purchased license from devart for dotConnect for oracle recently.

Thanks,

---

Hi,

I have resolved this error by setting up [DataServiceKey] attribute with primary key on each POCO classes. Please refer this: http://blog.marcgravell.com/2008/12/astoria-and-linq-to-sql-getting-started.html.

Now I can expose entities through Odata service but when I try to access the entity collection by typing URL (ex. .../WcfDataService1.svc/Assets) it throws following error:

Error:

 <?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>

How do I resolve this?

Thanks,

Answer 1

To use WCF DataService with EF6, there're some extra work to do. Please check the following two blog posts for detail:

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

In general, you'll need the following two steps:

1. Install the latest Nuget package Microsoft.OData.EntityFrameworkProvider following the guide on that page;

2. Replace DataService with EntityFrameworkDataService, say in your WcfDataService1.svc:

   public class WcfDataService1 : EntityFrameworkDataService