学步园

写了一个数据库操作类，达到通过实体自动映射数据库进行查询，添加，删除，修改操作,啥也不说了，直接上代码：

反回一个实体，通过枚举参数确定使用属性/特性进行字段映射(转款做表和主键映射)

/// <summary>
        /// 获取单个实体
        /// </summary>
        /// <typeparam name="TEntity">实体(泛型)</typeparam>
        /// <param name="cmdText">命令</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="exeEntityType">按属性/特性映射</param>
        /// <param name="paramers">参数数组</param>
        /// <returns>实体</returns>
        public static TEntity GetEntity<TEntity>(string cmdText, CommandType commandType,AppEnum.ExeEntityType exeEntityType,params DbParameter[] paramers) where TEntity:new()
        {
            TEntity entity = new TEntity();
            using (IDataReader reader = DbHelper.CreateDataReader(cmdText, commandType, paramers))
            {
                if (reader.Read())
                {
                    Type entityType = entity.GetType();
                    PropertyInfo[] propertyInfos=entityType.GetProperties();
                    foreach(PropertyInfo property in propertyInfos)
                    {
                        if (exeEntityType == AppEnum.ExeEntityType.isAttribute)
                        {
                            DataFieldAttribute datafieldAttribute = GetDataFieldAttribute(property);
                            if (datafieldAttribute == null)
                                throw new AssionException("AppEnum.ExeEntityType枚举为 isAttribute 时,实体类需要指定特性！");
                            if (!(reader[datafieldAttribute.FieldName] is DBNull))
                                property.SetValue(entity, reader[datafieldAttribute.FieldName], null);
                        }
                        else if (exeEntityType == AppEnum.ExeEntityType.isProperty)
                        {
                            if (!(reader[property.Name] is DBNull))
                                property.SetValue(entity, reader[property.Name], null);
                        }
                    }
                }
                reader.Close();
                reader.Dispose();
            }
            return entity;
        }

返回一个实体集合，类似上面的

/// <summary>
        /// 获取实体集合
        /// </summary>
        /// <typeparam name="TEntity">实体(泛型)</typeparam>
        /// <param name="cmdText">命令</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="exeEntityType">按属性/特性映射</param>
        /// <param name="paramers">参数数组</param>
        /// <returns>实体集合</returns>
        public static IList<TEntity> GetEntityList<TEntity>(string cmdText, CommandType commandType, AppEnum.ExeEntityType exeEntityType, params DbParameter[] paramers) where TEntity : new()
        {
            IList<TEntity> entityList = new List<TEntity>();
            using (IDataReader reader = DbHelper.CreateDataReader(cmdText, commandType, paramers))
            {
                while (reader.Read())
                {
                    TEntity entity = new TEntity();
                    Type entityType = entity.GetType();
                    PropertyInfo[] propertyInfos = entityType.GetProperties();
                    foreach (PropertyInfo property in propertyInfos)
                    {
                        if (exeEntityType == AppEnum.ExeEntityType.isAttribute)
                        {
                            DataFieldAttribute datafieldAttribute = GetDataFieldAttribute(property);
                            if (datafieldAttribute == null)
                                throw new AssionException("AppEnum.ExeEntityType枚举为 isAttribute 时,实体类需要指定特性！");
                            if (!(reader[datafieldAttribute.FieldName] is DBNull))
                                property.SetValue(entity, reader[datafieldAttribute.FieldName], null);
                        }
                        else if (exeEntityType == AppEnum.ExeEntityType.isProperty)
                        {
                            if (!(reader[property.Name] is DBNull))
                                property.SetValue(entity, reader[property.Name], null);
                        }                        
                    }
                    entityList.Add(entity);
                }
            }
            return entityList;
        }

执行SQL实体映射操作,可以写INSERT、UPDATE、DELETE 操作，这样灵活些，抽时间再完成个自动映射生成SQL的，不过灵活性就差些了

 /// <summary>
        /// 插入，更新，删除数据库实体
        /// </summary>
        /// <typeparam name="TEntity">实体(泛型)</typeparam>
        /// <param name="cmdText">命令</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="exeEntityType">按属性/特性映射</param>
        /// <param name="entity">实体</param>
        /// <returns>影响行数</returns>
        public static int ExeEntity<TEntity>(string cmdText, CommandType commandType, AppEnum.ExeEntityType exeEntityType,TEntity entity) where TEntity : new()
        {
            Type entityType = entity.GetType();
            PropertyInfo[] propertyInfos = entityType.GetProperties();
            List<DbParameter> paramerList = new List<DbParameter>();
            foreach (PropertyInfo property in propertyInfos)
            {
                if (exeEntityType == AppEnum.ExeEntityType.isAttribute)
                {
                    DataFieldAttribute datafieldAttribute = GetDataFieldAttribute(property);
                    if (datafieldAttribute == null)
                        throw new AssionException("AppEnum.ExeEntityType枚举为 isAttribute 时,实体类需要指定特性！");
                    object oval=property.GetValue(entity,null);
                    oval = oval == null ? DBNull.Value : oval;
                    paramerList.Add(DbHelper.CreateParamer("@" + datafieldAttribute.FieldName, oval));
                }
                else if (exeEntityType == AppEnum.ExeEntityType.isProperty)
                {
                    object oval = property.GetValue(entity, null);
                    oval = oval == null ? DBNull.Value : oval;
                    paramerList.Add(DbHelper.CreateParamer("@" + property.Name, oval));
                }
            }
            int retval=DbHelper.ExecuteNonQuery(cmdText, commandType, paramerList.ToArray());

            return retval;
        }

下面是字段的自定义特性和获取特性的代码：

    /// <summary>
    /// 自定义特性：映射数据库字段名
    /// </summary>
    [AttributeUsage(AttributeTargets.Struct|AttributeTargets.Property|AttributeTargets.Field)]
    public class DataFieldAttribute:Attribute
    {
        private string _fieldName; //字段名
        public string FieldName
        {
            get { return _fieldName; }
            set { _fieldName = value; }
        }

        public DataFieldAttribute(string fieldName)
        {
            this._fieldName = fieldName;
        }
    }

/// <summary>
        /// 获取DataFieldAttribute特性
        /// </summary>
        /// <param name="property">属性</param>
        /// <returns>DataFieldAttribute</returns>
        private static DataFieldAttribute GetDataFieldAttribute(PropertyInfo property)
        {
            object[] oArr=property.GetCustomAttributes(true);
            for(int i=0;i<oArr.Length;i++)
            {
                if(oArr[i] is DataFieldAttribute)
                    return (DataFieldAttribute)oArr[i];
            }
            return null;
        }

使用示例：
首先实体加上特性：

    public class People
    {
        [PrimaryKey()]
        [DataField("DbName")]
        public string Name { get; set; }
        [DataField("DbTel")]
        public string tel { get; set; }
    }

调用代码：
获取一个实体集合：

 IList<People> peopleList = ExecuteEntity.GetEntityList<People>("SELECT DbName,DbTel FROM Test", CommandType.Text, AppEnum.ExeEntityType.isAttribute, null);

向数据库插入实体数据：

ExecuteEntity.ExeEntity<People>("INSERT INTO Test (DbName,DbTel) VALUES (@DbName,@DbTel)", CommandType.Text, AppEnum.ExeEntityType.isAttribute, people);

最后再附上一个基础的数据库操作类：

/// <summary>
    /// 通用数据库帮助类
    /// </summary>
    public static class DbHelper
    {
        #region 连接配置读取

        /// <summary>
        /// 数据库类型
        /// </summary>
        private static readonly string dataProvider = ConfigurationManager.ConnectionStrings["ConnectionString"].ProviderName;

        /// <summary>
        /// 反射数据库类型
        /// </summary>
        private static readonly DbProviderFactory dataFactory = DbProviderFactories.GetFactory(dataProvider);

        /// <summary>
        /// 数据库连接字符串
        /// </summary>
        private static readonly string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;

        #endregion

        #region 连接命令

        /// <summary>
        /// 创建连接
        /// </summary>
        /// <returns>dbconnection</returns>
        public static DbConnection CreateConnection()
        {
            DbConnection dbConn = dataFactory.CreateConnection();
            dbConn.ConnectionString = connectionString;
            return dbConn;
        }

        /// <summary>
        /// 创建命令
        /// </summary>
        /// <param name="cmdText">命令</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="paramers">参数数组</param>
        /// <returns>command</returns>
        public static DbCommand CreateCommand(string cmdText,CommandType commandType,params DbParameter[] paramers)
        {
            DbConnection dbConn=CreateConnection();
            dbConn.Open();
            DbCommand dbCmd = dataFactory.CreateCommand();
            dbCmd.Connection = dbConn;
            dbCmd.CommandText = cmdText;
            dbCmd.CommandType = commandType;
            if(paramers!=null)
                dbCmd.Parameters.AddRange(paramers);

            return dbCmd;
        }

        #endregion

        #region 数据执行方法

        /// <summary>
        /// 创建带参数的只读器
        /// </summary>
        /// <param name="cmdText">命令</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="paramers">参数数组</param>
        /// <returns>reader</returns>
        public static DbDataReader CreateDataReader(string cmdText, CommandType commandType, params DbParameter[] paramers)
        {
            DbDataReader reader = null;
            reader = CreateCommand(cmdText, commandType, paramers).ExecuteReader(CommandBehavior.CloseConnection);
            return reader;
        }

        /// <summary>
        /// 创建无参数的只读器
        /// </summary>
        /// <param name="cmdText">命令</param>
        /// <param name="commandType">命令类型</param>
        /// <returns>reader</returns>
        public static DbDataReader CreateDataReader(string cmdText, CommandType commandType)
        {
            DbDataReader reader = null;
            reader = CreateCommand(cmdText, commandType, null).ExecuteReader(CommandBehavior.CloseConnection);           
            return reader;
        }

        /// <summary>
        /// 执行一个带参数的SQL/存储过程
        /// </summary>
        /// <param name="cmdText">命令</param>
        /// <param name="commandType">命令类型</param>
        /// <param name="paramers">参数数组</param>
        /// <returns>影响行数</returns>
        public static int ExecuteNonQuery(string cmdText, CommandType commandType, params DbParameter[] paramers)
        {
            int retval = CreateCommand(cmdText, commandType, paramers).ExecuteNonQuery();
            return retval;
        }

        /// <summary>
        /// 执行一个不带参数的SQL/存储过程
        /// </summary>
        /// <param name="cmdText">命令</param>
        /// <param name="commandType">命令类型</param>
        /// <returns>影响行数</returns>
        public static int ExecuteNonQuery(string cmdText, CommandType commandType)
        {
            int retval = CreateCommand(cmdText, commandType, null).ExecuteNonQuery();
            return retval;
        }

        /// <summary>
        /// 执行一个带参数的SQL/存储过程有事务的
        /// </summary>
        /// <param name="tran">事务</param>
        /// <param name="cmdText">命令</param>
        /// <param name="commmandType">命令类型</param>
        /// <param name="paramers">参数数组</param>
        /// <returns>影响行数</returns>
        public static int ExecuteNonQuery(DbTransaction tran,string cmdText,CommandType commmandType,params DbParameter[] paramers)
        {
            DbConnection dbConn = tran.Connection;
            DbCommand dbCmd=dataFactory.CreateCommand();
            dbCmd.Connection=dbConn;
            dbCmd.CommandType=commmandType;
            dbCmd.CommandText=cmdText;
            dbCmd.Parameters.AddRange(paramers);
            dbCmd.Transaction = tran;
            int retval=dbCmd.ExecuteNonQuery();
            return retval;
        }

        /// <summary>
        /// 执行一个无参数的SQL/存储过程有事务的
        /// </summary>
        /// <param name="tran">事务</param>
        /// <param name="cmdText">命令</param>
        /// <param name="commmandType">命令类型</param>
        /// <returns>影响行数</returns>
        public static int ExecuteNonQuery(DbTransaction tran, string cmdText, CommandType commmandType)
        {
            DbConnection dbConn = tran.Connection;
            DbCommand dbCmd = dataFactory.CreateCommand();
           

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