EntityFramework 6.1 cannot connect

Question

I have a class library I have been using for over a year that has recently stopped working after upgrading to EF 6.1.

I have tried various methods for passing in the connect string to my Context class constructor but while it seems to correctly pass the string I invariably receive:

'(((System.Data.Entity.DbContext)(context)).Database.Connection).ServerVersion' threw an exception of type 'System.InvalidOperationException'

and the connection state stays closed.

Here is my AppConfig:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>

    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 --></configSections>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0" />
  </startup>
  <connectionStrings>
    <add name="MyContext" connectionString="Data Source=Server;Initial Catalog=DBName;Integrated Security=True;MultipleActiveResultSets=True" providerName="System.Data.SqlClient" />
  </connectionStrings>
  <entityFramework>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
</configuration>

My test class:

using System.Data.Entity;

namespace SVMIC.IMS.Entity.IMSClaim
{
    public class Context:DbContext
    {
        static Context()
        {
            Database.SetInitializer<Context>(null);
        }

        public Context():base("MyContext")
        {
        }
    }
}

and my test app:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using SVMIC.IMS.Entity.IMSClaim;

namespace TestApp
{
  public partial class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();

      Context context = new Context();

    }
  }
}

The database server is SQL Server 2008 R2.

I assume it is something simple changed in 6.1 and I am just missing it, but I am totally stumped.

Answer 1

Ok, I have resolved the issue.

In frustration at not being able to fix the issue with 6.1, nothing I did made any difference to the result, and even building and stepping through the EF source accomplished little so I rolled back to EF 5.0 and rebuilt my code.

EF 5 immediately returned an error message identifying an issue in the schema definition, a view added by another developer that referenced system views was confusing my template, I fixed the issue and was back working in a matter of minutes.

The lesson learned here was, EF 6 needs some serious work on its error handling, as just returning a generic exception error left me chasing off in every direction, while the error message from EF 5 pointed me directly at the issue.

Answer 2

Based on the comments what appears to have happened is:

• The original EF Upgrade did not work, so you were still running on the old EF
• When you made the code change, the rebuild triggered that you would use the New EF
• But the New EF dll's are not available, so you get the error.

Check you config: the EF Version is 6.0 not 6.1, also the Public key token is the same as for .net 2.0.

Answer 3

Just for information on this error

I was configuring Repository and Unit of Work Design Pattern with EF 6.1 with a simple test database named as "School"

It had following 3 tables

BookMaster

Library and

Student

I had created their respective Entity classes, Configurations classes, Repository classes and also created DB Sets in Entities class.

After few days I had created one more table whose above mentioned classes and DbSets were not created.

What I found is providing connectionstring name in base() constructor parameter was giving me following error

'(context.Database.Connection).ServerVersion' threw an exception of type >'System.InvalidOperationException' entity framework 6.1

However if I pass complete connection string as a parameter to base() method then it was working.

After some Trial and Error I deleted the 4th table that was created and It worked like a dream. So may be it is necessary to utilize all the tables and create the above mentioned classes and DbSets which may resolve this issue

Answer 4

If you are working local MDF file, the update the folder path of MDF file in App.config/ Web.config else copy the dbmx App.cofig connectionStrings and paste to your project App.config/Web.config file.