Entity Framework Provider type could not be loaded?

Question 1

Same problem, but i installed EF 6 through Nuget. EntityFramework.SqlServer was missing for another executable. I simply added the nuget package to that project.

Question 2

I had the same problem in my Test projects - I installed the latest EF6 bits via NuGet and everytime I invoke something EF-related I got:

The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' for the 'System.Data.SqlClient' ADO.NET provider could not be loaded. Make sure the provider assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information.

My workaround: I placed this method inside my test project:

public void FixEfProviderServicesProblem()
{
//The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer'
//for the 'System.Data.SqlClient' ADO.NET provider could not be loaded. 
//Make sure the provider assembly is available to the running application. 
//See http://go.microsoft.com/fwlink/?LinkId=260882 for more information.

var instance = System.Data.Entity.SqlServer.SqlProviderServices.Instance;
}

This method is never been called, but I think the compiler will remove all "unnecessary" assemblies and without using the EntityFramework.SqlServer stuff the test fails.

Anyways: Works on my machine ;)

Note: Instead of adding the method to test project you can ensure a static reference to SqlProviderServices from your Model/entity project.

Question 3

Nuget will configure your EF6 project to reference EntityFramework.SqlServer.dll. This deploys to the output folder for your EF6 project during build, but it will not deploy to the output folder for projects referencing your EF6 project. I believe this is because Visual Studio is "smart" enough to detect that nothing in your assembly is actually using the dll directly and so does not include it. You can force EntityFramework.SqlServer.dll to be deployed to the output folder of projects referencing your EF6 project (unit tests, UI's etc.) by adding code to your EF6 project that uses EntityFramework.SqlServer.dll. Be careful not to put the code in a generated class as you risk losing it on next regen. I chose to add the following class to the assembly, which fixed the problem.

using System.Data.Entity.SqlServer;

internal static class MissingDllHack
{
    // Must reference a type in EntityFramework.SqlServer.dll so that this dll will be
    // included in the output folder of referencing projects without requiring a direct 
    // dependency on Entity Framework. See http://stackoverflow.com/a/22315164/1141360.
    private static SqlProviderServices instance = SqlProviderServices.Instance;
}

Question 4

My solution was to remove the entity framework from the project via the nuget manager and add it back in.

Question 5

I solved this by adding an using stament on top of my DBContext class, like so:

using SqlProviderServices= System.Data.Entity.SqlServer.SqlProviderServices;

Question 6

I've used Code-based registration for provider. link1 link2

Just created the configuration class like

class DbContextConfiguration : DbConfiguration
{
    public DbContextConfiguration()
    {
        this.SetDatabaseInitializer(new DropCreateDatabaseAlways<MyDbContext>());
        this.SetProviderServices(SqlProviderServices.ProviderInvariantName, SqlProviderServices.Instance);
    }
}

Key point is this.SetProviderServices(SqlProviderServices.ProviderInvariantName, SqlProviderServices.Instance);

and used it in the such way

[DbConfigurationType(typeof(DbContextConfiguration))]
public class MyDbContext : DbContext
{
    public MyDbContext()
    {
        ...
    }

    public DbSet<...> ...{ get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        ...
    }
}

Question 7

I sorted it out with [DeploymentItem] on my assembly initializing class

namespace MyTests
{
    /// <summary>
    /// Summary description for AssemblyTestInit
    /// </summary>
    [TestClass]
    [DeploymentItem("EntityFramework.SqlServer.dll")]
    public class AssemblyTestInit
    {
        public AssemblyTestInit()
        {
        }

        private TestContext testContextInstance;

        public TestContext TestContext
        {
            get
            {
                return testContextInstance;
            }
            set
            {
                testContextInstance = value;
            }
        }

        [AssemblyInitialize()]
        public static void DbContextInitialize(TestContext testContext)
        {
            Database.SetInitializer<TestContext>(new TestContextInitializer());
        }
    }
}

Question 8

I have problem, because I don't add reference to EntityFramework.sqlServer.dll. When I develop program, it works. But when I publish app and install it, it throws error.

I just add reference and Build and Publish again.

References

Question 9

Late to the party, but the top voted answers all seemed like hacks to me.

All I did was remove the following from my app.config in the test project. Worked.

  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="mssqllocaldb" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>

Question 10

I have solved this by manually copying EntityFramework.SqlServer.dll file to the bin folder of the main application.

Question 11

I see similar problem, and using the method from this post: (http://entityframework.codeplex.com/workitem/1590), which solves my problem.

To work around the issue you can make your test assembly directly reference the provider assembly by adding some line like this anywhere in the test assembly: var _ = System.Data.Entity.SqlServer.SqlProviderServices.Instance;

Question 12

I had same isssue i tried many times but it did not resolve but when i install the package EntityFramework.SqlServerCompact it solved install this package from Nuget package Manager.

Install-Package EntityFramework.SqlServerCompact

Question 13

I finally resolved this. Turns out, I had an erroneous implementation of IDIsposable in my repository class. I fixed that. The erroneous implementation caused a stackoverflow exception since I wasn't disposing off resources properly. This caused VS not to run the tests and the test execution engine crashed.

I filed it with Microsoft here ( this was before I got the correct solution). connect.microsoft.com/VisualStudio/feedback/details/775868/vs-test-execution-crashes-in-vs-2012#details

Anyway, the builds now run fine on teamcity. ALthough, I am still curious why neither VS Test execution engine had a graceful way of telling me what was happening not Team City.

I discovered the root cause by manually debugging the test ( which I only realised after so many days , the fix took me 5 seconds).

Hopefully this will help someone who comes across such issues.

Question 14

When I inspected the problem, I have noticed that the following dll were missing in the output folder. The simple solution is copy Entityframework.dll and Entityframework.sqlserver.dll with the app.config to the output folder if the application is on debug mode. At the same time change, the build option parameter "Copy to output folder" of app.config to copy always. This will solve your problem.

Question 15

Simply reference or browser the EF dll - EntityFramework.SqlServer.dll

Question 16

I've created a static "startup" file and added the code to force the DLL to be copied to the bin folder in it as a way to separate this 'configuration'.

[DbConfigurationType(typeof(DbContextConfiguration))] public static class Startup { }



public class DbContextConfiguration : DbConfiguration
{
    public DbContextConfiguration()
    {
        // This is needed to force the EntityFramework.SqlServer DLL to be copied to the bin folder
        SetProviderServices(SqlProviderServices.ProviderInvariantName, SqlProviderServices.Instance);
    }
}

Question 17

After trying all other suggested solutions and don't getting my project to work, I finally found a little comment in this page:

Deleting the BIN-Folder did it for me

And it worked for me too.

Question 18

I didn't want a reference to EF in my application project (or to manually copy anything) so I added this to my EF project's Post-build events:

cp $(TargetDir)EntityFramework.SqlServer.dll $(SolutionDir){your-main-bin-folder}

Question 19

This only happens inside my load/unit testing projects. Frustrating, I jyst had it crop up in a project I have been running for 2 years. Must have been some order of test running that breaks things. I guess once that fi gets removed its gone.

I found that simply declaring a variable that uses the correct value fixes the issue... I never even call the method. Just define it. Odd but it works.

    /// <summary>
    /// So that the test runner copies dlls not directly referenced by the integration project
    /// </summary>
    private void referenceLibs()
    {
        var useless = SqlProviderServices.Instance;
    }

Question 20

I also had a similar problem

My problem was solved by doing the following:

Question 21

I had the same issue with Instantiating DBContext object from a unit test project. I checked my unit test project packages and I figured that EntityFramework package was not installed, I installed that from Nuget and problem solved (I think it's EF bug).

happy coding

Question 22

Adding Entityframework.dll and Entityframework.sqlserver.dll to the reference project solved the issue.

Question 23

I checked Debug Output window in Unit Test project. EntityFramework.SqlServer.dll was not loaded. After adding it to the bin folder tests were run successfully.

Question 24

I just had the same error message.

I have a separate project for my data access. Running the Web Project (which referenced the data project) locally worked just fine. But when I deployed the web project to azure the assembly: EntityFramework.SqlServer was not copied. I just added the reference to the web project and redeployed, now it works.

hope this helps others

Question 25

I was working on the Contoso University tutorial offline and encountered the same issue when trying to create my first controller using EF. I had to use the Package Manager Console to load EF from the nuget cache and created a connection string to my local instance of SQL Server, my point here is my webConfig setting for EF may not be set as you all out there but I was able to resolve my issue by completely deleting the "providers" section within "entityFramework"

Robert

Question 26

There is a easy fix. open the references in your project, right click "System.Data" -> properties. Change "Copy Local" to "True".

Problem should be fixed.

Question 27

In my case I resolved the problem by installing SQL Server 2012 Developer Edition when I had previously installed SQL Server Express 2012 (x64). It seems that provided me with the missing dependency.

Question 28

remove the entity framework from the project via nuget then add it back in.

Question 29

In my case dll was not copied although I added a reference to it. This is because EntityFramework.SqlServer.dllis not copied into your project. Add that dll and it will hopefully work.You can find that from the project where you added datamodel.

Question 30

Additional to all useful suggestions here, if you are using EF 6.1.3, get sure your project's .net version is 4.5 or more.