.net – SQLite EF6在运行时以编程方式设置连接字符串

这是我们的app.config

<?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="testContext" connectionString="data source=Datatestdb.sqlite;Foreign Keys=True"
      providerName="System.Data.SQLite" />
  </connectionStrings>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory,EntityFramework">
      <parameters>
        <parameter value="v11.0" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SQLite" type="System.Data.SQLite.EF6.SQLiteProviderServices,System.Data.SQLite.EF6" />
    </providers>
  </entityFramework>
  <system.data>
    <DbProviderFactories>
      <remove invariant="System.Data.SQLite" />
      <remove invariant="System.Data.SQLite.EF6" />
      <add name="System.Data.SQLite" invariant="System.Data.SQLite" description=".Net Framework Data Provider for SQLite (Entity Framework 6)" type="System.Data.SQLite.EF6.SQLiteProviderFactory,System.Data.SQLite.EF6" />
    </DbProviderFactories>
  </system.data>
</configuration>

这里是DbContext

public class FirmwareContext : DbContext
{
    public FirmwareContext()
        : this(DEFAULT_CONNECTION)
    {

    }

    public FirmwareContext(string connextionNameOrString)
        : base(connextionNameOrString)
    {

    }
}

如果我连接来自app.config的连接名称,所有的工作都没有问题.如果我尝试传递与第二个构造函数的连接字符串,这将失败

这里是一个小例子

SQLiteConnectionStringBuilder builder =
    factory.CreateConnectionStringBuilder() as SQLiteConnectionStringBuilder;
builder.DataSource = dataSource; // Path to file name of the user
builder.ForeignKeys = true;

var context = new FirmwareContext(builder.ToString());

var context = new FirmwareContext(builder.ToString());
var test = context.Firmware.FirstOrDefault();

我得到以下例外(“Schlüsselwortwird nichtunterstützt：”外键“.)=>关键的“外键”不支持.如果我删除外键集,我得到以下异常(“提供程序没有返回一个ProviderManifestToken字符串”)和一些内部异常.

似乎bas(connectionString)构建MSSQL连接字符串和SQLite.

我如何使我的第二个构造函数与sqlite相容？

public DbContext(DbConnection existingConnection,bool contextOwnsConnection);

使用此覆盖可以传递一个SQLiteConnection,而不是设置连接字符串.所以例如你可以添加一个新的构造函数到您的FirmwareContext.

public FirmwareContext(string connectionString)
    : base(new SQLiteConnection() { ConnectionString = connectionString },true)
{
}

甚至

public FirmwareContext(string filename)
    : base(new SQLiteConnection() { ConnectionString =
            new SQLiteConnectionStringBuilder()
                { DataSource = filename,ForeignKeys = true }
            .ConnectionString },true)
{
}

（编辑：李大同）

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