具有不变名称'System.Data.SqlClient;'的ADO.NET提供程序 无法找到(实体框架MVC)

Question

我似乎无法解决实体框架6中似乎是一个常见问题.我已经在SO上回顾了与此问题相关的许多主题,并且无法找到适用于我的特定情况的解决方案.

到目前为止,我一直在使用带有代码优先迁移的localdb进行开发,这很好.但是现在我将它移动到实际的SQL服务器实例,它会在尝试迁移时抛出以下错误:

"具有不变名称'System.Data.SqlClient;'的ADO.NET提供程序 要么没有在机器或应用程序配置文件中注册,要么无法加载.有关详细信息,请参阅内部异常.在System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName)"

我尝试了以下修复:

1)卸载并重新安装的实体框架

2)添加了代码并使用:

public abstract class BaseDomainContext : DbContext
{
    static BaseDomainContext()
    {
        // ROLA - This is a hack to ensure that Entity Framework SQL Provider is copied across to the output folder.
        // As it is installed in the GAC, Copy Local does not work. It is required for probing.
        // Fixed "Provider not loaded" error
        var ensureDLLIsCopied = System.Data.Entity.SqlServer.SqlProviderServices.Instance;
    }
}

作为我的DbSet类的基类.

3)将所有内容添加到新的解决方案并收到相同的错误.

4)删除了writecontext并尝试了只读的迁移,仍然失败了.

5)使用来自MSDN的信息尝试了几次重写

6)我已经确认EntityFramework.SqlServer.dll在我的bin目录中.它也被正确引用.另外,我的解决方案只有一个项目.

7)确认我没有在视图下使用WebConfig.

8)确认我在bin文件夹中有System.Data dll.

清理/重建和删除在上述每个步骤之后完成的现有迁移文件夹.

我无法解释为什么我仍然收到此错误.

Web配置

    <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>
  <appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
  </appSettings>
  <connectionStrings>

    <add name="ReadContext" connectionString="Server=Sql2014intsnace;Database=database;User Id=secret; Password=secret;" providerName="System.Data.SqlClient;" />
    <add name="WriteContext" connectionString="Server=Sql2014intsnace;Database=database;User Id=secret; Password=secret;" providerName="System.Data.SqlClient;" />
  </connectionStrings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5" />
    <authentication mode="Windows" />
    <authorization>
      <deny users="?" />
    </authorization>
  </system.web>
  <system.webServer>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
  </system.webServer>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security.OAuth" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security.Cookies" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-5.2.2.0" newVersion="5.2.2.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />    
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
    <contexts> 
  <context type="ProjectName.Models.ReadContext, ProjectName"> 
    <databaseInitializer type="System.Data.Entity.MigrateDatabaseToLatestVersion`2[[ProjectName.Models.ReadContext, ProjectName], [ProjectName.Migrations.Configuration, ProjectName]], EntityFramework" /> 
  </context> 
</contexts>
  </entityFramework>
</configuration>

Answer 1

你有这个:

<add name="ReadContext" 
     connectionString="Server=Sql2014intsnace;Database=database;User Id=secret; Password=secret;" 
     providerName="System.Data.SqlClient;" /> <-- semi-colon

它应该是这样的:

<add name="ReadContext" 
     connectionString="Server=Sql2014intsnace;Database=database;User Id=secret; Password=secret;" 
     providerName="System.Data.SqlClient" /> <-- no semi-colon

否则,你告诉ADO找到一个名为的提供者System.Data.SqlClient;- 没有一个.