EF6+MYSQL之初体验

初次使用EF6+MYSQL

这次的项目时间可拉得够长的,定制开发就是这样。客户真正用上了才能基本上不再改了。起先项目是php实现的，改造成桌面程序。用.net winform开发,像这种小项目肯定要用EF了。 以前一直用4.0，用DB First，把向导生成的模型扩展一下，另写一个分部类来实现bulkcopy等这种特殊需求。一直都是这样简单的用着，懒得花时间成本去搞高深的AOP/IOC/泛型工厂... 有时候就是越简单越好，当只会捉老鼠的猫就好。 这次依然还是使用的DB First。

经验总结：

1、EF6之CRUD

EF向导自动转换成的DbContext类:

public partial class POS_Entities : DbContext
    {
        public POS_Entities()
            : base("name=POS_Entities")
        {
        }
    
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            throw new UnintentionalCodeFirstException();
        }
    
        public virtual DbSet<bm_brandclasses> bm_brandclasses { get; set; }
        public virtual DbSet<bm_brandsubclasses> bm_brandsubclasses { get; set; }
        public virtual DbSet<bm_membermng> bm_membermng { get; set; }
        public virtual DbSet<bm_memcard_privilege> bm_memcard_privilege { get; set; }
        public virtual DbSet<bm_memcardclasses> bm_memcardclasses { get; set; }
        public virtual DbSet<bm_pointmng> bm_pointmng { get; set; }
        public virtual DbSet<ls_busimng> ls_busimng { get; set; }
        public virtual DbSet<ls_cashierlist> ls_cashierlist { get; set; }
        public virtual DbSet<ls_cashierlist_detail> ls_cashierlist_detail { get; set; }
        public virtual DbSet<ls_cashiernum> ls_cashiernum { get; set; }
        public virtual DbSet<ls_commoditymng> ls_commoditymng { get; set; }
        public virtual DbSet<ls_couponmng> ls_couponmng { get; set; }
        public virtual DbSet<ls_couponmng_list> ls_couponmng_list { get; set; }
        public virtual DbSet<ls_handovermng> ls_handovermng { get; set; }
        public virtual DbSet<ls_promotionclasses> ls_promotionclasses { get; set; }
        public virtual DbSet<ls_promotionmng> ls_promotionmng { get; set; }
        public virtual DbSet<ls_promotionmng_subact> ls_promotionmng_subact { get; set; }
        public virtual DbSet<ls_promotionsubclasses> ls_promotionsubclasses { get; set; }
        public virtual DbSet<sa_manager> sa_manager { get; set; }
        public virtual DbSet<sa_num_auto> sa_num_auto { get; set; }
        public virtual DbSet<sa_role> sa_role { get; set; }
        public virtual DbSet<ls_leasemng> ls_leasemng { get; set; }
    }

我的扩展类：

public partial class POS_Entities
    {
        private static readonly BindingFlags bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.Static | BindingFlags.NonPublic;

        private static readonly Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
        public string ConnectionString
        {
            get
            {
                var ecb = new EntityConnectionStringBuilder(config.ConnectionStrings.ConnectionStrings["POS_Entities"].ConnectionString);
                return ecb.ProviderConnectionString;
            }
        }
        /// <summary>
        /// 执行Sql语句
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public int ExecuteSql(string sql)
        {
            return this.Database.ExecuteSqlCommand(sql, new object[] { });
        }

        /// <summary>
        /// 返回查询的第一行第一列的值
        /// </summary>
        /// <param name="sqlText"></param>
        /// <returns></returns>
        public object ExecuteScalar(string sqlText)
        {
            var db = this.Database.Connection;
            try
            {
                if (db.State != ConnectionState.Open)
                    db.Open();
                var cmd = db.CreateCommand();
                cmd.CommandText = sqlText;
                return cmd.ExecuteScalar();
            }
            finally
            {
                db.Close();
            }
        }

        /// <summary>
        /// 使用同一个事物批量提交SQL
        /// </summary>
        /// <param name="sqls"></param>
        public bool BatchExecuteSqlWithTrans(List<string> sqls)
        {
            var dbConn = this.Database.Connection;
            if (dbConn.State != ConnectionState.Open)
                dbConn.Open();
            var cmd = dbConn.CreateCommand();
            var st = dbConn.BeginTransaction();
            try
            {
                HashSet<string> list = new HashSet<string>();
                cmd.Transaction = st;
                sqls.ForEach(delegate (string sqlTxt)
                {
                    cmd.CommandText = sqlTxt;
                    cmd.ExecuteNonQuery();
                });
                st.Commit();
                return true;
            }
            catch (Exception ex)
            {
                st.Rollback();
                return false;
                throw new Exception(ex.Message);
            }
            finally
            {
                dbConn.Close();
            }
        }

        #region MySql 批量插入
        /// <summary>
        /// 批量插入
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="tbName">要插入的目标表名称</param>
        /// <param name="columeArr">要插入的列名数组</param>
        /// <param name="listModels">要插入的实体数组</param>
        /// <param name="strConnection">数据库连接字符串</param>
        /// <returns></returns>
        public int BatchInsert<T>(string tbName, string[] columeArr, IList<T> listModels) where T : class, new()
        {
            if (listModels == null || listModels.Count == 0)
            {
                throw new ArgumentException("没有需要批量插入的数据");
            }
            int columes = columeArr.Length;
            StringBuilder sb = new StringBuilder();
            sb.AppendFormat("INSERT INTO {0} ", tbName);
            AppendColumes(sb, columeArr);
            sb.Append(" VALUES ");
            var listParamKeys = new List<string>();//参数的键值
            string paramKey = string.Empty;
            for (int i = 0; i < listModels.Count; i++)  //构造参数
            {
                sb.Append("(");
                for (int j = 0; j < columes; j++)
                {
                    paramKey = string.Format("@v_{0}_{1}", columeArr[j], columes * i + j); //参数前必须加入@
                    sb.Append(paramKey);
                    listParamKeys.Add(paramKey);
                    if (j < columes - 1)
                    {
                        sb.Append(",");
                    }
                }
                sb.Append("),");
            }
            var listParamValues = new List<object>();
            for (int i = 0; i < listModels.Count; i++)  //构造参数值数组
            {
                FastPrepareParamValue<T>(listModels[i], columeArr, listParamValues);
            }
            string sqlText = sb.ToString().Trim(',') + ";";
            int affectNum = ExecuteNonQuery(ConnectionString, CommandType.Text, sqlText, PrepareParameters(listParamKeys.ToArray(), listParamValues.ToArray()));
            return affectNum;
        }
        private int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
        {
            MySqlCommand cmd = new MySqlCommand();
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                PrepareCommand(conn, null, cmd, cmdType, cmdText, commandParameters);
                int val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return val;
            }
        }
        private MySqlParameter[] PrepareParameters(string[] paramKeys, object[] paramValues)
        {
            MySqlParameter[] clonedParms = new MySqlParameter[paramKeys.Length];
            for (int i = 0; i < paramKeys.Length; i++)
            {
                clonedParms[i] = new MySqlParameter(paramKeys[i], paramValues[i]);
            }
            return clonedParms;
        }
        private void PrepareCommand(MySqlConnection conn, MySqlTransaction trans, MySqlCommand cmd, CommandType cmdType, string cmdText, MySqlParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = cmdType;
            if (cmdParms != null)
            {
                foreach (MySqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }

        private void AppendColumes(StringBuilder sb, string[] columeArr)
        {
            if (columeArr == null || columeArr.Length == 0)
            {
                throw new ArgumentException("插入列不能为空");
            }
            sb.Append("(");
            for (int i = 0; i < columeArr.Length; i++)
            {
                sb.Append(columeArr[i]);
                if (i < columeArr.Length - 1)
                {
                    sb.Append(",");
                }
            }
            sb.Append(")");
        }

        private void FastPrepareParamValue<T>(T model, string[] columeArr, List<object> listPramValues)
        {
            object objValue = null;
            var objType = model.GetType();
            var properties = objType.GetProperties(bf);
            foreach (var columeName in columeArr)
            {
                foreach (var propInfo in properties)
                {
                    if (string.Compare(columeName, propInfo.Name, true) != 0)
                    {
                        continue;
                    }
                    try
                    {
                        objValue = propInfo.GetValue(model);
                    }
                    catch
                    {
                        objValue = null;
                    }
                    finally
                    {
                        listPramValues.Add(objValue);
                    }
                    break;
                }
            }
        }
        #endregion

        public DataSet Query(CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
        {
            MySqlCommand cmd = new MySqlCommand();
            MySqlConnection conn = new MySqlConnection(ConnectionString);
            try
            {
                PrepareCommand(conn, null, cmd, cmdType, cmdText, commandParameters);
                MySqlDataAdapter adapter = new MySqlDataAdapter();
                adapter.SelectCommand = cmd;
                DataSet ds = new DataSet();
                adapter.Fill(ds);
                cmd.Parameters.Clear();
                conn.Close();
                return ds;
            }
            catch (Exception e)
            {
                throw e;
            }
        }
    }

扩展类的目的是使用熟悉的原生ado.net的方式来避免趟EF的坑（未必有的）。　

1)增 

db.cashierlist.Add(bill);
                    try
                    {
                        db.Entry<cashierlist>(bill).State = System.Data.Entity.EntityState.Added;
                        db.SaveChanges();
                        result.Success = true;
                        result.Message = "操作成功！";
                        result.Result = bill;
                    }
                    catch (Exception ex)
                    {
                        var exx = ex.InnerException == null ? ex : ex.InnerException;
                        result.Message = exx.Message;
                    }

这里好像就是需要写"db.Entry<T>(bill).State = System.Data.Entity.EntityState.Added",显式的标记为"System.Data.Entity.EntityState.Added",即新增状态。

2)改和删好像跟以前一样的没啥说的。

3)查

var dbExists = db.ls_cashierlist.SqlQuery("select * from ls_cashierlist where cl_sn='" + bill.cl_sn + "'").FirstOrDefaultAsync().Result;

toListAsync()/FirstOrDefaultAsync()/SingleAsync()等陌生方法给我带来了困惑。以前同步方式调用这些api习惯了，现在统统变成了支持异步的方法了。不深究，改成同步的方式就是取XXX方法的().Result就行了。

2、关于.net连接mysql

1)MYSQL某些字段日期时间类型如果是允许空值时且存了空值那么，MYSQL默认写的是“0000-00-00 00：00：00”这样子，这个其实在连接字符串里面有几个选项可以参考一下，就是"allowzerodatetime"和"convertzerodatetime".

2)中文乱码，需要指定字符集，比如：characterset=utf8

3、Http get或者post请求超时时间控制

由于winform客户端在发起Http get或者post请求时刚开始设置的超时时间是5秒，后来发现请求在服务器端的webapi中处理时间比较久时，客户端就直接什么都不返回，自动被终止了，两边都没有异常。自动被超时时间这个参数处理掉了。

还以为是那些个异步方法的使用有问题就是说webapi在返回值的时候没有等到异步方法返回就开始返回给客户端了。这是错误的，前面已经把异步改成同步了。

后来增加超时时间就能正常返回了。记录一下，我自己能看懂就好

还是老规矩，晒上几张图作为结束：