entity-framework - mvc - entity framework versions




No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient' (20)

Add below to your app.config.

 <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v11.0" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>

After downloading the EF6 by nuget and try to run my project, it returns the following error:

No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient'. Make sure the provider is registered in the 'entityFramework' section of the application config file. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information.


Add this function

private void FixEfProviderServicesProblem()

to database context class in the library class and the missing DLL EntityFramework.SqlServer.dll will be copied to the correct places.

namespace a.b.c
{
    using System.Data.Entity;

    public partial class WorkflowDBContext : DbContext
    {
        public WorkflowDBContext()
            : base("name=WorkflowDBConnStr")
        {
        }

        public virtual DbSet<WorkflowDefinition> WorkflowDefinitions { get; set; }
        public virtual DbSet<WorkflowInstance> WorkflowInstances { get; set; }
        public virtual DbSet<EngineAlert> EngineAlerts { get; set; }
        public virtual DbSet<AsyncWaitItem> AsyncWaitItems { get; set; }
        public virtual DbSet<TaskItem> TaskItems { get; set; }
        public virtual DbSet<TaskItemLink> TaskItemLinks { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
        }

        private 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;
        }
    }
}

.


As message shows that we need to add provider System.Data.SqlClient that's why we need to install nuget package of EntityFramework that has two dll but if we are developing only console application then we just need to add reference of EntityFramework.SqlServer.dll


Deleting the BIN-Folder did it for me


I also had a similar problem.My problem was solved by doing the following:


I got the same error while using Entity Framework 6 with SQL Server Compact 4.0. The article on MSDN for Entity Framework Providers for EF6 was helpful. Running the respective provider commands as nuget packages at Package Manager Console might solve the problem, as also NuGet packages will automatically add registrations to the config file. I ran PM> Install-Package EntityFramework.SqlServerCompact to solve the problem.


I had one console application and class library. In class library I created Entity Data Model (right click to Class Library > Add > New Item > Data > ADO.NET Entity Data Model 6.0) and put reference inside console application. So, you have console application which has reference to class library and inside class library you have EF model. I had the same error when I tried to get some records from the table.

I resolved this issue by following these steps:

  1. Right click to solution and choose option 'Manage NuGet Packages for Solution' and NuGet package manager window will show up.
  2. Go to 'Manage' option under 'Installed packages' TIP: Entity Framework is added to Class Library, so you will have EntityFramework under 'Installed packages' and you'll see 'Manage'option
  3. Click on 'Manage' option and check to install package to project which has reference to class library which holds EF model (in my case I set check box to install package to console app which had reference to class library which had EF model inside)

That's all I had to do and everything worked perfect.

I hope it helped.


I had the identical exception thrown. I included

using System.Data; 
using System.Data.Entity;

and everything is back to working again ..



I have the same error. It's weird that it only happens whenever I used my dbContext to query to any of my model or get its list like:

var results = _dbContext.MyModel.ToList();

We tried to reinstall the Entity Framework, reference it properly but to no avail.

Luckily, we tried to check the Nuget for ALL solutions, then update everything or make sure everything is the same version because we noticed that the two projects has different EF versions on the Web project. And it works. The error is gone.

Here is the screenshot on how to Manage Nuget for all solutions:


I just run into this problem today. I have data repository class library with EF63 NuGet package and console application for testing, which have reference only to class library project. I created very simple post-build command, which copies EntityFramework.SqlServer.dll from class library's Bin\Debug folder to console application's Bin\Debug folder and problem solved. Do not forget to add entityFramework section to console application's .config file.


I tried almost all the above and nothing worked.

Only when I set the referenced DLLs in the Default Project EntityFramework and EntityFramework.SqlServer properties Copy Local to True did it start working!


Instead of adding EntityFramework.SqlServer to host project you can ensure a static reference to it from your Model/entity project like this

static MyContext()
{
    var type = typeof(System.Data.Entity.SqlServer.SqlProviderServices);
    if(type == null)
        throw new Exception("Do not remove, ensures static reference to System.Data.Entity.SqlServer");
}

This will make the build process include the assembly with the host project.

More info on my blog http://andersmalmgren.com/2014/08/20/implicit-dependencies-and-copy-local-fails-to-copy/


None of these worked for me. I did find the solution in another question. I'll add it here for easy reference:

You need to make a reference, so it will be copied in den application path. Because later it will be referenced in runtime. So you don't need to copy any files.

private volatile Type _dependency;

public MyClass()
{
    _dependency = typeof(System.Data.Entity.SqlServer.SqlProviderServices);
}

Ran into this problem today when working with a set of web services, each in different projects, and a separate project containing integration tests for some of those services.

I've been using this setup for some time with EF5, without needing to include references to EF from the Integration Test Project.

Now, after upgrading to EF6, it seems I need to include a reference to EF6 in the integration test project too, even though it is not used there (pretty much as pointed out above by user3004275).

Indications you're facing the same problem:

  • Calls directly to EF (connecting to a DB, getting data, etc) work fine, as long as they are initiated from a project that has references to EF6.
  • Calls to the service via a published service interface work fine; i.e. there are no missing references "internally" in the service.
  • Calls directly to public methods in the service project, from a project outside the service, will cause this error, even though EF is not used in that project itself; only internally in the called project

The third point is what threw me off for a while, and I'm still not sure why this is required. Adding a ref to EF6 in my Integration Test project solved it in any case...


The startup project that references the project where Entity Framework is being used needs the following two assemblies in it's bin folder:

  • EntityFramework.dll
  • EntityFramework.SqlServer.dll

Adding a <section> to the <configSections> of the .config file on the startup project makes the first assembly available in that bin directory. You can copy this from the .config file of your Entity Framework project:

<configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>

To make the second .dll available in the bin folder, although not practical, a manual copy from the bin folder of the Entity Framework project can be made. A better alternative is to add to the Post-Build Events of the Entity Framework project the following lines, which will automate the process:

cd $(ProjectDir)
xcopy /y bin\Debug\EntityFramework.SqlServer.dll ..\{PATH_TO_THE_PROJECT_THAT_NEEDS_THE_DLL}\bin\Debug\

When you install Entity Framework 6 through Nuget. EntityFramework.SqlServer sometime miss for another executable. Simply add the Nuget package to that project.

Sometimes above does not work for Test Project

To solve this issue in Test Project just place this Method inside Test Project:

public void FixEfProviderServicesProblem()
{
    var instance = System.Data.Entity.SqlServer.SqlProviderServices.Instance;
}

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


You can also see this message if you forget to include "EntityFramework.SqlServer.dll".

It appears to be a newly added file in EF6. Initially I hadn't included it in my merge module and ran into the problem listed here.


You should force a static reference to the EntityFramework.SqlServer.dll assembly, but instead of putting a dummy code, you can do this in a more beautiful way:

  1. If you already have a DbConfiguration class:

    public class MyConfiguration : DbConfiguration
    {
        public MyConfiguration()
        {
            this.SetProviderServices(System.Data.Entity.SqlServer.SqlProviderServices.ProviderInvariantName, System.Data.Entity.SqlServer.SqlProviderServices.Instance);
        }
    }
    
  2. If you don't have a DbConfiguration class you must put the following code at app startup (before EF is used):

    static MyContext()
    {
        DbConfiguration.Loaded += (sender, e) =>
            e.ReplaceService<DbProviderServices>((s, k) => System.Data.Entity.SqlServer.SqlProviderServices.Instance);
    }
    

You've added EF to a class library project. You also need to add it to the project that references it (your console app, website or whatever).







entity-framework