c# – 没有app.config的实体框架代码

https://stackoverflow.com/a/15919627/941240

诀窍是稍微修改默认的MigrateDatabaseToLatestVersion初始化程序,以便：

>数据库始终初始化…
> …使用当前上下文中的连接字符串

DbMigrator仍将创建新的数据上下文,但会根据初始化程序从您的上下文中复制连接字符串.我甚至能够缩短代码.

它在这里：

public class MasterDetailContext : DbContext
{
    public DbSet<Detail> Detail { get; set; }
    public DbSet<Master> Master { get; set; }

    // this one is used by DbMigrator - I am NOT going to use it in my code
    public MasterDetailContext()
    {
        Database.Initialize( true );
    }

    // rather - I am going to use this,I want dynamic connection strings
    public MasterDetailContext( string ConnectionString ) : base( ConnectionString )
    {
        Database.SetInitializer( new CustomInitializer() );
        Database.Initialize( true );
    }

    protected override void  OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
    }
}

public class CustomInitializer : IDatabaseInitializer<MasterDetailContext>
{

    #region IDatabaseInitializer<MasterDetailContext> Members

    // fix the problem with MigrateDatabaseToLatestVersion 
    // by copying the connection string FROM the context
    public void InitializeDatabase( MasterDetailContext context )
    {            
        Configuration cfg = new Configuration(); // migration configuration class
        cfg.TargetDatabase = new DbConnectionInfo( context.Database.Connection.ConnectionString,"System.Data.SqlClient" );

        DbMigrator dbMigrator = new DbMigrator( cfg );
        // this will call the parameterless constructor of the datacontext
        // but the connection string from above will be then set on in
        dbMigrator.Update();             
    }

    #endregion
}

客户代码：

static void Main( string[] args )
    {

        using ( MasterDetailContext ctx = new MasterDetailContext( @"Database=ConsoleApplication801;Server=.SQL2012;Integrated Security=true" ) )
        {
        }

        using ( MasterDetailContext ctx = new MasterDetailContext( @"Database=ConsoleApplication802;Server=.SQL2012;Integrated Security=true" ) )
        {
        }
    }

运行此命令将导致根据迁移配置创建和迁移两个数据库.