EF代码优先MigrateDatabaseToLatestVersion接受来自配置的连接字符串名称 [英] EF Code First MigrateDatabaseToLatestVersion accepts connection string Name from config

问题描述

试图在我的项目中实施EF迁移时，我被困在一个地方。

While trying to implement EF Migrations in my project I am stuck at one place.

EF代码优先MigrateDatabaseToLatestVersion接受来自配置的连接字符串名称。

EF Code First MigrateDatabaseToLatestVersion accepts connection string Name from config.

在我的情况下，在运行时知道数据库名称（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名称的方式一样， MigrateDatabaseToLatestVersion不接受相同的

In my case database name get known at Runtime (User selects it from dropdown). Just the way DbContext either accepts, ConnectionString or connectionString Name in it's constructor, "MigrateDatabaseToLatestVersion" does not accept the same

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

还有其他方法可以实现这一目标吗？

Is there any other way to achieve this?

推荐答案

谢谢大家。我确实从codeplex中签出了EF代码，并在理解了它们的源代码之后继承了我自己的类。这是我选择的解决方案：-

Thank you all. I did checkout the EF code from codeplex, and inherited my own class after understanding their source code. Here is the solution which I opted :-

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;

        }
    }

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