EF Code First MigrateDatabaseToLatestVersion接受来自config的连接字符串Name

Question

在我的项目中尝试实施EF迁移时,我被困在一个地方.

EF Code First MigrateDatabaseToLatestVersion接受来自config的连接字符串Name.

在我的情况下,数据库名称在运行时得知(用户从下拉列表中选择它).就像DbContext在其构造函数中接受,ConnectionString或connectionString Name的方式,"MigrateDatabaseToLatestVersion"不接受相同的

System.Data.Entity.Database.SetInitializer
(new MigrateDatabaseToLatestVersion<SrcDbContext, SRC.DomainModel.ORMapping.Migrations.Configuration>(connString));

有没有其他方法来实现这一目标？

Answer 1

谢谢你们.我从codeplex中检出了EF代码,并在理解了它们的源代码后继承了我自己的类.这是我选择的解决方案: -

public class MigrateDbToLatestInitializerConnString<TContext, TMigrationsConfiguration> : IDatabaseInitializer<TContext>
        where TContext : DbContext
        where TMigrationsConfiguration : DbMigrationsConfiguration<TContext>, new()
    {
        private readonly DbMigrationsConfiguration config;

        /// <summary>
        ///     Initializes a new instance of the MigrateDatabaseToLatestVersion class.
        /// </summary>
        public MigrateDbToLatestInitializerConnString()
        {
            config = new TMigrationsConfiguration();
        }

        /// <summary>
        ///     Initializes a new instance of the MigrateDatabaseToLatestVersion class that will
        ///     use a specific connection string from the configuration file to connect to
        ///     the database to perform the migration.
        /// </summary>
        /// <param name="connectionString"> connection string to use for migration. </param>
        public MigrateDbToLatestInitializerConnString(string connectionString)
        {
            config = new TMigrationsConfiguration
                          {
                              TargetDatabase = new DbConnectionInfo(connectionString, "System.Data.SqlClient")
                          };
        }

        public void InitializeDatabase(TContext context)
        {
            if (context == null)
            {
                throw new ArgumentException("Context passed to InitializeDatabase can not be null");
            }

            var migrator = new DbMigrator(config);

            migrator.Update();
        }
    }

 public static class DatabaseHelper
    {
        /// <summary>
        /// This method will create data base for given parameters supplied by caller.
        /// </summary>
        /// <param name="serverName">Name of the server where database has to be created</param>
        /// <param name="databaseName">Name of database</param>
        /// <param name="userName">SQL user name</param>
        /// <param name="password">SQL password</param>
        /// <returns>void</returns>
        public static bool CreateDb(string serverName, string databaseName, string userName, string password)
        {
            bool integratedSecurity = !(!string.IsNullOrEmpty(userName) || !string.IsNullOrEmpty(password));

            var builder = new System.Data.SqlClient.SqlConnectionStringBuilder
                {
                    DataSource = serverName,
                    UserID = userName,
                    Password = password,
                    InitialCatalog = databaseName,
                    IntegratedSecurity = integratedSecurity,
                };


            var db = new SrcDbContext(builder.ConnectionString);

            var dbInitializer = new MigrateDbToLatestInitializerConnString<SrcDbContext, SRC.DomainModel.ORMapping.Migrations.Configuration>(builder.ConnectionString);

            //following uses strategy to "CreateIfNotExist<>"
            dbInitializer.InitializeDatabase(db);

            return true;

        }
    }

Answer 2

您可以使MigrateDatabaseToLatestVersion初始化程序使用最初触发迁移的上下文所使用的连接字符串。如docs中所述，通过将useSuppliedContext：true传递给MigrateDatabaseToLatestVersion构造函数来完成。在您的情况下：

Database.SetInitializer(new MigrateDatabaseToLatestVersion<SrcDbContext, SRC.DomainModel.ORMapping.Migrations.Configuration>(useSuppliedContext: true));