DataServieException: Oracle, EFOracleProvider, POCO and EF 4.0 - oracle

Question

I try to use the new POCO capabilities of EF 4.0 in combination with the EFOracleProvider. I have recompiled the EFOracleProvider (using ODAC instead of System.Data.OracleClient) to target the .NET Framework 4 (und put it in the 4.0 GAC). Everything ok so far.
I host the Entity Model in a WCF Data Service:
class DivaDispoDataService : DataService<DivaDispoContainer>
{
public static void InitializeService(IDataServiceConfiguration config)
{
config.SetEntitySetAccessRule("*", EntitySetRights.All);
config.SetServiceOperationAccessRule("*", ServiceOperationRights.All);
}
}
My EDMX File looks like this:
<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="2.0" xmlns:edmx="http://schemas.microsoft.com/ado/2008/10/edmx">
<!-- EF Runtime content -->
<edmx:Runtime>
<!-- SSDL content -->
<edmx:StorageModels>
<Schema xmlns="http://schemas.microsoft.com/ado/2009/02/edm/ssdl" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" Namespace="DivaDispo.Store" Alias="Self" Provider="EFOracleProvider" ProviderManifestToken="10g">
<EntityContainer Name="DivaDispoStoreContainer">
<EntitySet Name="DIW_USER" EntityType="DivaDispo.Store.DIW_USER" store:Type="Tables" Schema="" />
</EntityContainer>
<EntityType Name="DIW_USER">
<Key>
<PropertyRef Name="IDX" />
</Key>
<Property Name="IDX" Type="number" Nullable="false" Precision="10" />
<Property Name="USERNAME" Type="number" Precision="10" />
<Property Name="PERSONNELNUMBER" Type="number" Precision="10" />
<Property Name="PASSWORD" Type="varchar2" MaxLength="10" />
<Property Name="ACTIVATED" Type="number" Precision="1" />
<Property Name="ROLE" Type="number" Precision="1" />
</EntityType>
</Schema>
</edmx:StorageModels>
<!-- CSDL content -->
<edmx:ConceptualModels>
<Schema xmlns="http://schemas.microsoft.com/ado/2008/09/edm" xmlns:cg="http://schemas.microsoft.com/ado/2006/04/codegeneration" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" Namespace="DivaDispo.Model" Alias="Self" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation">
<EntityContainer Name="DivaDispoContainer" annotation:LazyLoadingEnabled="false">
<EntitySet Name="User" EntityType="DivaDispo.Model.User" />
</EntityContainer>
<EntityType Name="User">
<Key>
<PropertyRef Name="ID" />
</Key>
<Property Name="ID" Type="Decimal" Nullable="false" Precision="10" Scale="0" />
<Property Name="Username" Type="Decimal" Precision="10" Scale="0" />
<Property Name="PersonnelNumber" Type="Decimal" Precision="10" Scale="0" />
<Property Name="Password" Type="String" MaxLength="10" Unicode="false" FixedLength="false" />
<Property Name="Activated" Type="Boolean" />
<Property Name="Role" Type="Boolean" />
</EntityType>
</Schema>
</edmx:ConceptualModels>
<!-- C-S mapping content -->
<edmx:Mappings>
<Mapping xmlns="http://schemas.microsoft.com/ado/2008/09/mapping/cs" Space="C-S">
<EntityContainerMapping StorageEntityContainer="DivaDispoStoreContainer" CdmEntityContainer="DivaDispoContainer">
<EntitySetMapping Name="User">
<EntityTypeMapping TypeName="IsTypeOf(DivaDispo.Model.User)">
<MappingFragment StoreEntitySet="DIW_USER">
<ScalarProperty Name="ID" ColumnName="IDX" />
<ScalarProperty Name="Username" ColumnName="USERNAME" />
<ScalarProperty Name="PersonnelNumber" ColumnName="PERSONNELNUMBER" />
<ScalarProperty Name="Password" ColumnName="PASSWORD" />
<ScalarProperty Name="Activated" ColumnName="ACTIVATED" />
<ScalarProperty Name="Role" ColumnName="ROLE" />
</MappingFragment>
</EntityTypeMapping>
</EntitySetMapping>
</EntityContainerMapping>
</Mapping>
</edmx:Mappings>
</edmx:Runtime>
</edmx:Edmx>
My POCO Class looks like this:
public partial class User
{
public virtual decimal ID { get; set; }
public virtual Nullable<decimal> Username { get; set; }
public virtual Nullable<decimal> PersonnelNumber { get; set; }
public virtual string Password { get; set; }
public virtual Nullable<bool> Activated { get; set; }
public virtual Nullable<bool> Role { get; set; }
}
and the DataContext like this:
public partial class DivaDispoContainer : ObjectContext
{
public const string ConnectionString = "name=DivaDispoContainer";
public const string ContainerName = "DivaDispoContainer";
#region Constructors
public DivaDispoContainer()
: base(ConnectionString, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = false;
}
public DivaDispoContainer(string connectionString)
: base(connectionString, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = false;
}
public DivaDispoContainer(EntityConnection connection)
: base(connection, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = false;
}
#endregion
#region ObjectSet Properties
public ObjectSet<User> User
{
get { return _user ?? (_user = CreateObjectSet<User>("User")); }
}
private ObjectSet<User> _user;
}
The POCO classes and the DataContext are generated with the POCO Template from Visual Studio 2010.
When I start my WCF Service and want to query the users I receive an System.Data.Services.DataServiceException which says somtihng like
500: Internal Server error. The type 'System.Data.Entity.DynamicProxies.User_057822846B2B8DD7BB03058490B27D19E6C634EACF33438FE886 19C8BBB1CF74' is not a komplex type or entity type.
When I look in the dubgger I can see that the values have been read from the database (therefore I think the EFOracleProvider works ok) and that the DynamicProxies.User_.... is derrived from my User class (which contains at that point the data from the database). So the question is: Why do I receive this exception? Does anyone know whats going on there? What's the DynamicProxies.User_.... automaic generated class for? The Exception is thrown in the Method GetNonPrimitiveResourceType of the class WebUtil. Or maybe I have something overlooked?
Any help greatly appreciated....

Answer 1

The link from Craig to the blog post http://msdn.microsoft.com/en-us/library/ee705457.aspx revealed the answer. It states there that
The POCO proxy type cannot be directly serialized or deserialized by WCF
and that is exactly my problem. If I remove the virtual from the properties of the genrated POCO class the runtime doesnt generate the proxy types and the exception dissapears.
Thanks again for the link, Craig.