public class ConnectionFactory
    {
        /// <summary>
        /// 获取数据库连接
        /// </summary>
        /// <param name="dbtype">数据库类型</param>
        /// <param name="conStr">数据库连接字符串</param>
        /// <returns>数据库连接</returns>
        public static IDbConnection CreateConnection(string strConn, string dbtype = "sqlserver")
        {
            if (string.IsNullOrWhiteSpace(strConn))
                throw new Exception("database conectionstring is required");
            return CreateConnections(strConn, dbtype);
        }

        /// <summary>
        /// 获取数据库连接
        /// </summary>
        /// <param name="dbType">数据库类型</param>
        /// <param name="conStr">数据库连接字符串</param>
        /// <returns>数据库连接</returns>
        public static IDbConnection CreateConnections(string strConn, string dbtype)
        {
            IDbConnection connection = null;
            
            switch (dbtype)
            {
                case "sqlserver":
                    connection = new SqlConnection(strConn);
                    break;
                case "mysql":
                    connection = new MySqlConnection(strConn);
                    break;
            }
            if (connection.State == ConnectionState.Closed)
            {
                connection.Open();
            }
            return connection;
        }
    }