即使已更改，实体框架仍尝试连接到旧的ADO.NET提供程序

Question

I changed a MySQL project's DB connection to target SQL Server from MySQL. However, when trying to run Update-Database -StartProjectName ProjectName targeting a database in SQL Server, I receive the following error

Schema specified is not valid. Errors: (0,0) : error 0152: No Entity Framework provider found for the ADO.NET provider with invariant name 'MySql.Data.MySqlClient'. 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.

So I tried to ensure that my project was free of MySQL

1. Use ctrl+F and search for all MySQL keyword : Found none.
2. Uninstall MySQL packages via NuGET package manager

Why does Entity Framework keep asking me for MySQL provider when I have clearly indicated that it should use the default MS SQL provider in the config file?

This is my config file:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <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>
  <connectionStrings>
   <add name="Connection" connectionString="Data Source=SQLSERVER123;Database=DB123;Integrated Security=true" providerName="System.Data.SqlClient" />
  </connectionStrings>
  <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>
</configuration>

---

This is my DbContext file:

using System;
using System.Data.Entity;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;

namespace ProjectName.MSSQL
{
    public class ProjectNameContext:DbContext
    {
        public ProjectNameContext()
            : base("Connection")
        {

        }

        public static ProjectNameContext Create()
        {
            return new ProjectNameContext();
        }

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

Answer 1

So what worked for me was I created my own DbConfiguration class and referenced it using the codeConfigurationType property in App.config

My custom Dbconfiguration class

using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Data.Entity.SqlServer;

namespace ProjectName.MSSQL
{
    public class MSSQLDbConfiguration:DbConfiguration
    {
        public MSSQLDbConfiguration()
        {
            this.SetProviderServices("System.Data.SqlClient", System.Data.Entity.SqlServer.SqlProviderServices.Instance);
            this.SetDefaultConnectionFactory(new LocalDbConnectionFactory("v11.0"));
        }
    }
}

My App.config

<entityFramework codeConfigurationType="ProjectName.MSSQL.MSSQLDbConfiguration, ProjectName.MSSQL">
...
any stuff...
...
</entityFramework>