How do I solve The Entity Framework provider exception

问题

I have published my WCF project onto a server, i have also published an MVC application onto the same box which consumes the WCF services.

When trying login on my MVC application, this uses a wcf service, but i get this exception on the browser,

The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application.

This is an entity framework exception, but i assume since my project already references EF in the dev environment, after deploying the service project, the DLLs should contain the EF reference also but I am not sure why I am getting this error.

I can see this message because I turned on the includeExceptionDetailInFaults="True"

回答1:

@FranciscoGoldenstein saying ! You don't need to install Entity Framework in your Console application or whatever, you just need to add a reference to the assembly EntityFramework.SqlServer.dll. You can copy this assembly from the Class Library project that uses Entity Framework to a LIB folder and add a reference to it.

In summary:

Class Library application:
- Install Entity Framework
- Write your data layer code
- app.config file has all the configuration related to Entity Framework except for the connection string.
Create a Console, web or desktop application:
- Add a reference to the first project.
- Add a reference to EntityFramework.SqlServer.dll.
- app.config/web.config has the connection string (remember that the name of the configuration entry has to be the same as the name of the DbContext class.

it is work for me ! I hope it helps.

also try this link Entity Framework Provider type could not be loaded?

回答2:

The easiest trick to resolve this issue is to add the following line inside one of the classes in your EF project:

public class Blablabla
{
    private static string __hack = typeof(SqlProviderServices).ToString();

    // other class members as they were before.
}

This will force the build process to copy EntityFramework.SqlServer.dll to the \bin folder of any project that has references to the EF project.

No need to install EF nuget package or make an explicit reference to EntityFramework.SqlServer.dll in any downstream project.