asp.net mvc, CS0012: The type 'System.Data.Objects.DataClasses.EntityObject' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.

after I located the Entity framework connection string, Unable to load the specified metadata resource. continued reading the professional asp.net mvc 2 to page 48. When I try to run the details page. /controller/details/validid
get the following error,

Compilation Error Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. Compiler Error Message: CS0012: The type 'System.Data.Objects.DataClasses.EntityObject' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. Source Error: Line 170: Line 171: [System.Runtime.CompilerServices.CompilerGlobalScopeAttribute()] Line 172: public class views_dinners_details_aspx : System.Web.Mvc.ViewPage<LADinner.Models.Dinner>, System.Web.SessionState.IRequiresSessionState, System.Web.IHttpHandler { Line 173: Line 174: private static bool @__initialized; Source File: c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\f41f3cb9\3196a0b\App_Web_details.aspx.32d6c807.yjqx_sl8.0.cs    Line: 172

the stack trace shows when runtime try to compile the .aspx page using the csc.exe, missed one assembly reference System.Data.Entity.

then I click the detailed compiler output  , I get the following outputs. and Highlighted the System.Data.X assemblies. the error is right, there is no reference to System.Data.Entity.

"C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe" /t:library /utf8output /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.IdentityModel\v4.0_4.0.0.0__b77a5c561934e089\System.IdentityModel.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.WorkflowServices\v4.0_4.0.0.0__31bf3856ad364e35\System.WorkflowServices.dll" /R:"C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\f41f3cb9\3196a0b\App_global.asax.4lhx-qfz.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.Extensions\v4.0_4.0.0.0__31bf3856ad364e35\System.Web.Extensions.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_32\System.Data\v4.0_4.0.0.0__b77a5c561934e089\System.Data.dll" /R:"C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\f41f3cb9\3196a0b\App_Web_3rrpychx.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.Services\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Web.Services.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.Abstractions\v4.0_4.0.0.0__31bf3856ad364e35\System.Web.Abstractions.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Runtime.Serialization\v4.0_4.0.0.0__b77a5c561934e089\System.Runtime.Serialization.dll" /R:"C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\f41f3cb9\3196a0b\assembly\dl3\452a723b\f0bfe800_2e75cb01\NerdDinner.DLL" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\Microsoft.CSharp\v4.0_4.0.0.0__b03f5f7f11d50a3a\Microsoft.CSharp.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Core\v4.0_4.0.0.0__b77a5c561934e089\System.Core.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Configuration\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Activities\v4.0_4.0.0.0__31bf3856ad364e35\System.Activities.dll" /R:"C:\Windows\assembly\GAC_MSIL\System.Web.Mvc\2.0.0.0__31bf3856ad364e35\System.Web.Mvc.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System\v4.0_4.0.0.0__b77a5c561934e089\System.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Xml.Linq\v4.0_4.0.0.0__b77a5c561934e089\System.Xml.Linq.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_32\System.Web\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Web.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_32\System.EnterpriseServices\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.EnterpriseServices.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.ServiceModel.Web\v4.0_4.0.0.0__31bf3856ad364e35\System.ServiceModel.Web.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.Entity\v4.0_4.0.0.0__b77a5c561934e089\System.Web.Entity.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Xml\v4.0_4.0.0.0__b77a5c561934e089\System.Xml.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.ServiceModel.Activities\v4.0_4.0.0.0__31bf3856ad364e35\System.ServiceModel.Activities.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.ServiceModel\v4.0_4.0.0.0__b77a5c561934e089\System.ServiceModel.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.ComponentModel.DataAnnotations\v4.0_4.0.0.0__31bf3856ad364e35\System.ComponentModel.DataAnnotations.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Drawing\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Drawing.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.DynamicData\v4.0_4.0.0.0__31bf3856ad364e35\System.Web.DynamicData.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.ServiceModel.Activation\v4.0_4.0.0.0__31bf3856ad364e35\System.ServiceModel.Activation.dll" /R:"C:\Windows\Microsoft.NET\Framework\v4.0.30319\mscorlib.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Data.DataSetExtensions\v4.0_4.0.0.0__b77a5c561934e089\System.Data.DataSetExtensions.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.ApplicationServices\v4.0_4.0.0.0__31bf3856ad364e35\System.Web.ApplicationServices.dll" /R:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.Routing\v4.0_4.0.0.0__31bf3856ad364e35\System.Web.Routing.dll" /out:"C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\f41f3cb9\3196a0b\App_Web_details.aspx.32d6c807.yjqx_sl8.dll" /D:DEBUG /debug+ /optimize- /w:4 /nowarn:1659;1699;1701 /warnaserror-  "C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\f41f3cb9\3196a0b\App_Web_details.aspx.32d6c807.yjqx_sl8.0.cs" "C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\f41f3cb9\3196a0b\App_Web_details.aspx.32d6c807.yjqx_sl8.1.cs"

Then I did some research. Though we added the assembly System.Data.Entity into our project. which means that those assembly are only for Runtime reference. For Compile time reference, We have to add the reference to System.web/Compilation/Assemblies in web.config, then the csc will pick up this settings

Like

<compilation debug="true" targetFramework="4.0"> <assemblies> <add assembly="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add assembly="System.Web.Routing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> </assemblies> </compilation>