无法使用Entity Framework查找或加载Npgsql

Question

我完全迷失了.在Visual Studio 2015中,我创建了一个WCF库服务项目并定义了服务和服务接口.

使用NuGet控制台安装了EntityFramework,EntityFramework.SqlServer,EntityFramework6.Npgsql和Npgsql:

• PM> Install-Package EntityFramework6.Npgsql -Version 3.0.5

将库服务设置为启动然后启动调试(f5)正确读取可用的过程.但是,在测试WcfSvcHost中的任何过程时,我收到以下错误:

具有不变名称"Npgsql"的ADO.NET提供程序未在计算机或应用程序配置文件中注册,或者无法加载.有关详细信息,请参阅内部异常

我做错了什么？

这是App.config文件:

<?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" />
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
  </configSections>
  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" />
  </system.web>
  <!-- When deploying the service library project, the content of the config file must be added to the host's 
  app.config file. System.Configuration does not support config files for libraries. -->
  <system.serviceModel>
    <services>
      <service name="NovaMedicalService.MedicalService">
        <endpoint address="" binding="basicHttpBinding" contract="NovaMedicalService.IMedicalService">
          <identity>
            <dns value="localhost" />
          </identity>
        </endpoint>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8733/Design_Time_Addresses/NovaMedicalService/MedicalService/" />
          </baseAddresses>
        </host>
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <!-- To avoid disclosing metadata information, 
          set the values below to false before deployment -->
          <serviceMetadata httpGetEnabled="True" httpsGetEnabled="True" />
          <!-- To receive exception details in faults for debugging purposes, 
          set the value below to true.  Set to false before deployment 
          to avoid disclosing exception information -->
          <serviceDebug includeExceptionDetailInFaults="False" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v12.0" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
      <provider invariantName="Npgsql" type="Npgsql.NpgsqlServices, EntityFramework6.Npgsql" />
    </providers>
  </entityFramework>
  <connectionStrings>
    <add name="chaosEntities" connectionString="metadata=res://*/ChaosModel.csdl|res://*/ChaosModel.ssdl|res://*/ChaosModel.msl;provider=Npgsql;provider connection string=&quot;Database=chaos;Host=localhost;Password=yuyuyu;Username=ooosos&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
</configuration>

有人可以帮忙吗？我完全迷失了.

TIA

Answer 1

问题解决了.我忽略了补充:

<system.data>
    <DbProviderFactories>
      <remove invariant="Npgsql" />
      <add name="Npgsql Data Provider" invariant="Npgsql" description=".Net Data Provider for PostgreSQL" type="Npgsql.NpgsqlFactory, Npgsql, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7" support="FF" />
    </DbProviderFactories>
  </system.data>

(请参阅Visual Studio支持(DDEX)