c# - SQLite 错误 : The 'DbProviderFactories' section can only appear once per config file (IBM Client Access)

Question

我在 .NET 4.5 上使用 WPF 和 C# 将 Entity Framework 和 System.Data.SQLite 用于我的应用程序在我的机器上运行良好，但在测试机器上，当我通过 EntityFramework 访问 sqlite 数据库时收到此错误:

The 'DbProviderFactories' section can only appear once per config file.

我发现错误是在测试机中，在machine.config中:

<system.data>
    <DbProviderFactories>
        <add name="IBM DB2 for i5/OS .NET Provider" invariant="IBM.Data.DB2.iSeries" description=".NET Framework Data Provider for i5/OS" type="IBM.Data.DB2.iSeries.iDB2Factory, IBM.Data.DB2.iSeries, Version=12.0.0.0, Culture=neutral, PublicKeyToken=9cdb2ebfb1f93a26"/>
        <add name="Microsoft SQL Server Compact Data Provider" invariant="System.Data.SqlServerCe.3.5" description=".NET Framework Data Provider for Microsoft SQL Server Compact" type="System.Data.SqlServerCe.SqlCeProviderFactory, System.Data.SqlServerCe, Version=3.5.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91"/>
        <add name="IBM DB2 for i .NET Provider" invariant="IBM.Data.DB2.iSeries" description=".NET Framework Data Provider for IBM i" type="IBM.Data.DB2.iSeries.iDB2Factory, IBM.Data.DB2.iSeries, Version=12.0.0.0, Culture=neutral, PublicKeyToken=9cdb2ebfb1f93a26" />
    </DbProviderFactories>
    <!-- This is the line to remove - empty element --> 
    <DbProviderFactories/>
</system.data>

我删除了最后一个空元素，现在一切正常了。我认为这与 IBM.Data.DB2.iSeries 安装(IBM 客户端访问)有关。

我的问题是:如何在不手动编辑 machine.config 的情况下删除空元素？我试图插入标签 <clear />在 app.config 文件中但不起作用。

我发现了另一个与我类似的问题，但没有人建议如何在不手动编辑 machine.config 的情况下解决问题。

这是我的 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=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <system.xml.serialization>
    <xmlSerializer useLegacySerializerGeneration="true" />
  </system.xml.serialization>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    <!--STAI MOLTO ATTENTO-->
    <legacyUnhandledExceptionPolicy enabled="1"/>
  </startup>
  <connectionStrings>
    <add name="db" connectionString="Data Source=clients.db;Version=3;New=False;Compress=True;" />
    <add name="icmdbEntities" connectionString="metadata=res://*/MainModel.csdl|res://*/MainModel.ssdl|res://*/MainModel.msl;provider=System.Data.SQLite;provider connection string=&quot;data source=.\icmdb.db&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v11.0" />
      </parameters>
    </defaultConnectionFactory>
  </entityFramework>
  <system.data>
    <DbProviderFactories>
      <clear />
      <remove invariant="System.Data.SQLite" />
      <add name="SQLite Data Provider" invariant="System.Data.SQLite" description=".Net Framework Data Provider for SQLite" type="System.Data.SQLite.SQLiteFactory, System.Data.SQLite" />
    </DbProviderFactories>
  </system.data>
  <appSettings>
    <add key="ditta" value="default" />
    <add key="demo" value="true"/>
    <add key="ClientSettingsProvider.ServiceUri" value="" />
  </appSettings>
  <system.web>
    <membership defaultProvider="ClientAuthenticationMembershipProvider">
      <providers>
        <add name="ClientAuthenticationMembershipProvider" type="System.Web.ClientServices.Providers.ClientFormsAuthenticationMembershipProvider, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" serviceUri="" />
      </providers>
    </membership>
    <roleManager defaultProvider="ClientRoleProvider" enabled="true">
      <providers>
        <add name="ClientRoleProvider" type="System.Web.ClientServices.Providers.ClientRoleProvider, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" serviceUri="" cacheTimeout="86400" />
      </providers>
    </roleManager>
  </system.web>
</configuration>

Answer 1

我今天遇到了这个问题。

machine.config文件位于:

• C:\Windows\Microsoft.NET\Framework\v2.0.50727\CONFIG\machine.config
• C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config\machine.config
• C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG\machine.config
• C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\machine.config

machine.config 的损坏版本包含:

<system.data>
   <DbProviderFactories>
      <add name="IBM DB2 for i .NET Provider" invariant="IBM.Data.DB2.iSeries" description=".NET Framework Data Provider for IBM i" type="IBM.Data.DB2.iSeries.iDB2Factory, IBM.Data.DB2.iSeries, Version=12.0.0.0, Culture=neutral, PublicKeyToken=9cdb2ebfb1f93a26" />
   </DbProviderFactories>
   <DbProviderFactories/>
</system.data>

安装 iSeries 驱动程序损坏了以下 machine.config文件:

| Framework | Platform | Factory Added? | Corrupted Machine.config? |
|-----------|----------|----------------|---------------------------|
|v4.0.30319 |   x64    |     Yes        |   Yes                     |
|v4.0.30319 |   x86    |     Yes        |   Yes                     |
|v2.0.50727 |   x86    |     No         |   No                      |
|v2.0.50727 |   x64    |     No         |   No                      |

很高兴您只需要担心 IBM 损坏一半的 machine.config文件；以及那些仅使用 .NET 4 的应用程序。

要修复的文件

• C:\Windows\Microsoft.NET\Framework\v2.0.50727\CONFIG\machine.config (好的)
• C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config\machine.config (好的)
• C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG\machine.config (腐败)
• C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\machine.config (腐败)

从提升权限的记事本中，打开这两个文件，并删除多余的空白 <DbProviderFactories/>元素，留给你:

<system.data>
   <DbProviderFactories>
      <add name="IBM DB2 for i .NET Provider" invariant="IBM.Data.DB2.iSeries" description=".NET Framework Data Provider for IBM i" type="IBM.Data.DB2.iSeries.iDB2Factory, IBM.Data.DB2.iSeries, Version=12.0.0.0, Culture=neutral, PublicKeyToken=9cdb2ebfb1f93a26" />
   </DbProviderFactories>
</system.data>

然后你就修好了。