'System.Data.Entity.Internal.AppConfig'的类型初始化程序在子网站上引发了一个例外

Question

I have 2 websites, one is a sub directory of another but is an Application ex: /root & /root/Services

They both use Entity Framework 6.x but the child website is throwing The type initializer for System.Data.Entity.Internal.AppConfig' threw an exception because it appears to be seeing to many entries for the same EF Database Provider because of the nested web.config

Is there a way to clear the providers collection so that I do not get this error? I've tried putting in which had no effect.

If I comment out providers section it works

<providers>
  <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>

But I don't want to do this because not every environment is going to have nested websites. and NuGet tends puts it back in. Can I adjust this programmatically?

Here's the full exception and stack trace

System.TypeInitializationException was unhandled by user code
HResult=-2146233036
Message=**The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception.**
Source=EntityFramework
TypeName=System.Data.Entity.Internal.AppConfig
StackTrace:
     at System.Data.Entity.Internal.AppConfig.get_DefaultInstance()
     at System.Data.Entity.Internal.LazyInternalConnection..ctor(String nameOrConnectionString)
     at System.Data.Entity.DbContext..ctor(String nameOrConnectionString)
     at co.Repository.Data.coContext..ctor() in coModel.Context.Generated.cs:line 23
     at co.Repository.RepositoryBase`1.SingleOrDefault(Expression`1 predicate) in co.Repository\RepositoryBase.cs:line 13
     at UserFactory.GetOneByUserName(String siteCode, String userName) in UserFactory.cs:line 151
     at UserService.GetOneByUserName(String siteCode, String userName) in UserService.cs:line 59
     at SyncInvokeGetOneByUserName(Object , Object[] , Object[] )
     at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
     at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
InnerException: System.Configuration.ConfigurationErrorsException
     HResult=-2146232062
     Message=An error occurred creating the configuration section handler for entityFramework: **The provider for invariant name 'System.Data.SqlClient' is specified multiple times in the application configuration. The invariant name must be unique for each configured provider.** (web.config line 339)
     Source=System.Configuration
     BareMessage=An error occurred creating the configuration section handler for entityFramework: The provider for invariant name 'System.Data.SqlClient' is specified multiple times in the application configuration. The invariant name must be unique for each configured provider.
     Filename=web.config
     Line=339
     StackTrace:
          at System.Configuration.BaseConfigurationRecord.EvaluateOne(String[] keys, SectionInput input, Boolean isTrusted, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult)
          at System.Configuration.BaseConfigurationRecord.Evaluate(FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult, Boolean getLkg, Boolean getRuntimeObject, Object& result, Object& resultRuntimeObject)
          at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject)
          at System.Configuration.BaseConfigurationRecord.GetSection(String configKey)
          at System.Configuration.ConfigurationManager.GetSection(String sectionName)
          at System.Data.Entity.Internal.AppConfig..ctor()
          at System.Data.Entity.Internal.AppConfig..cctor()
     InnerException: System.InvalidOperationException
          HResult=-2146233079
          Message=The provider for invariant name 'System.Data.SqlClient' is specified multiple times in the application configuration. The invariant name must be unique for each configured provider.
          Source=EntityFramework
          StackTrace:
               at System.Data.Entity.Internal.ConfigFile.ProviderCollection.BaseAdd(ConfigurationElement element)
               at System.Configuration.ConfigurationElementCollection.OnDeserializeUnrecognizedElement(String elementName, XmlReader reader)
               at System.Configuration.ConfigurationElement.DeserializeElement(XmlReader reader, Boolean serializeCollectionKey)
               at System.Configuration.ConfigurationElement.DeserializeElement(XmlReader reader, Boolean serializeCollectionKey)
               at System.Configuration.RuntimeConfigurationRecord.RuntimeConfigurationFactory.CreateSectionImpl(RuntimeConfigurationRecord configRecord, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentConfig, ConfigXmlReader reader)
               at System.Configuration.RuntimeConfigurationRecord.RuntimeConfigurationFactory.CreateSectionWithRestrictedPermissions(RuntimeConfigurationRecord configRecord, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentConfig, ConfigXmlReader reader)
               at System.Configuration.RuntimeConfigurationRecord.CreateSection(Boolean inputIsTrusted, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentConfig, ConfigXmlReader reader)
               at System.Configuration.BaseConfigurationRecord.CallCreateSection(Boolean inputIsTrusted, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentConfig, ConfigXmlReader reader, String filename, Int32 line)
          InnerException: 

Answer 1

I had the same issue.

I resolved this error by simply updating the version number from:

Version=5.0.0.0

to:

Version=6.0.0.0

Example:

<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, 

PublicKeyToken=b77a5c561934e089" requirePermission="false" />

Answer 2

I had an issue with EF 4.3.1 with a nested site.

Both sites were using the same library and connection strings...the error was caused by apparent duplicates in the

<connectionStrings>

It was presumably loading the connection strings from the parent site, and then failing to load the sub-site's strings.

In your sub-site, add:

<connectionStrings>
<clear/>
...your normal connection strings
</connectionStrings>

Answer 3

In EF6 you can use Code Base configuration - take a look at this article for more details.

EDIT

I checked in a change to EF6 code where exact duplicates are ignored. This should solve your problem. Note that this did not fit in the 6.0.2 release and should be included in the next release after 6.0.2.