Entity-framework – Request error with WCF Data Services

entity-frameworkodatawcf-data-services

Its my first time setting up an OData Service and I'm of course having some problems…

The problem is that I can't get the service running, I keep getting an "Request Error".
Request Error

I have researched on what the problem can be and I found that a common issue is that the access rules are incorrectly typed. So I have tried fixing this both with Singular names, Plural names and I have also tried with typeof(Post).getType().Name

Well here is my code. I hope you can help me, I've been stuck for hours.

public class ODataService : DataService<Entity>
{
    // This method is called only once to initialize service-wide policies.
    public static void InitializeService( DataServiceConfiguration config )
    {
        //config.SetEntitySetAccessRule( "Users", EntitySetRights.All );
        //config.SetEntitySetAccessRule( "Posts", EntitySetRights.All );
        //config.SetEntitySetAccessRule( "Albums", EntitySetRights.All );


        config.SetEntitySetAccessRule( "*", EntitySetRights.AllRead );
        config.SetServiceOperationAccessRule( "*", ServiceOperationRights.AllRead );
        //config.SetServiceOperationAccessRule( "GetPosts", ServiceOperationRights.AllRead );

        config.UseVerboseErrors = true;
        config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2;
    }

    [WebGet]
    public IQueryable<Post> GetPosts()
    {
        return CurrentDataSource.Posts.AsQueryable();
    }
}

The structure of my EntityFramework class (db first)
The structure of my EntityFramework class (db first)

Methods and Members for Entity class. Here the entities are spelled in plural.
Methods and Members for Entity class

This is my Web.config:

<?xml version="1.0"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <connectionStrings>
    <add name="Entity" connectionString="metadata=res://*/;provider=System.Data.SqlClient;provider connection string=&quot;data source=XXX;Initial Catalog=XXX;persist security info=True;user id=XXX;password=XXX;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
    <add key="ValidationSettings:UnobtrusiveValidationMode" value="WebForms" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime requestValidationMode="4.5" targetFramework="4.5" encoderType="System.Web.Security.AntiXss.AntiXssEncoder, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
    <pages controlRenderingCompatibilityVersion="4.5" />
    <machineKey compatibilityMode="Framework45" />
  </system.web>
<system.serviceModel>
    <services>
      <service name="LinkIT.Core.OData.ODataService"  behaviorConfiguration ="DebugEnabled">
      </service>
    </services>
    <behaviors>
      <serviceBehaviors >
        <behavior name="DebugEnabled">
          <serviceDebug includeExceptionDetailInFaults="True"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
  </system.serviceModel>
</configuration>

A detailed error message:

The server encountered an error processing the request. The exception
message is 'Value cannot be null. Parameter name:
propertyResourceType'. See server logs for more details. The exception
stack trace is:

at System.Data.Services.WebUtil.CheckArgumentNull[T](T value, String
parameterName) at
System.Data.Services.Providers.ResourceProperty..ctor(String name,
ResourcePropertyKind kind, ResourceType propertyResourceType) at
System.Data.Services.Providers.ObjectContextServiceProvider.PopulateMemberMetadata(ResourceType
resourceType, IProviderMetadata workspace, IDictionary2 knownTypes,
PrimitiveResourceTypeMap primitiveResourceTypeMap) at
System.Data.Services.Providers.ObjectContextServiceProvider.PopulateMetadata(IDictionary2
knownTypes, IDictionary2 childTypes, IDictionary2 entitySets) at
System.Data.Services.Providers.BaseServiceProvider.PopulateMetadata()
at System.Data.Services.Providers.BaseServiceProvider.LoadMetadata()
at
System.Data.Services.DataService1.CreateMetadataAndQueryProviders(IDataServiceMetadataProvider&
metadataProviderInstance, IDataServiceQueryProvider&
queryProviderInstance, BaseServiceProvider& builtInProvider, Object&
dataSourceInstance) at
System.Data.Services.DataService1.CreateProvider() at
System.Data.Services.DataService1.HandleRequest() at
System.Data.Services.DataService1.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)

Best Answer

WCF Data Services team confirms - this is the exact error faced when you use Enums (which is not yet supported).

Remove the Enum types (or use their suggested work-around and use a wrapper around the enum properties) and this should go away.

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