C# 利用反射方便取得DbDataReader里的值

概述

在我以前做项目时,读DbDataReder里的值时都会用Reader.Read()然后根据名字来逐个读出.自从学会利用反射来读后,一切变得很容易.

以前的做法

定义一个Entity

    public class FileInformationModel  
    {
        #region Public Property

        /// <summary>
        /// Gets and sets the file ID
        /// </summary>
        public string FileID { get; set; }

        /// <summary>
        /// Gets and sets the file name
        /// </summary>
        public string FileName { get; set; }

        /// <summary>
        /// Gets and sets the file save type
        /// </summary>
        public int? FileSaveType { get; set; }

        /// <summary>
        /// Gets and sets the file url
        /// </summary>
        public string FileUrl { get; set; }

        /// <summary>
        /// Gets and sets the file is new 
        /// </summary>
        public bool? IsNew { get; set; }

        /// <summary>
        /// Gets and sets the file last access time
        /// </summary>
        public DateTime? LastAccessTime { get; set; }

        /// <summary>
        /// Gets and sets the file modity time
        /// </summary>
        public DateTime? ModifyTime { get; set; }

        /// <summary>
        /// Gets and sets the file version
        /// </summary>
        public int? Version { get; set; }

        /// <summary>
        /// Gets and sets the file content owner
        /// </summary>
        public string ContentOwner { get; set; }

        /// <summary>
        /// Gets and sets the file content type
        /// </summary>
        public string ContentType { get; set; }

        /// <summary>
        /// Gets and sets the file create date time
        /// </summary>
        public DateTime? CreateTime { get; set; }

        /// <summary>
        /// Gets and sets the file access control
        /// </summary>
        public string FileAccessControl { get; set; }

        /// <summary>
        /// Gets and sets the file from
        /// </summary>
        public string FileFrom { get; set; }

        #endregion
    }

然后读取DbDataReader

        /// <summary>
        /// Execute reader by store procedure and parameter list
        /// </summary>
        /// <param name="cmdText">store procedure</param>
        /// <param name="parameters">parameter list</param>
        /// <returns>data reader</returns>
        public DbDataReader ExecuteReader(string cmdText, List<DbParameter> parameters,out DbConnection conn)
        {
            lock (lockObject)
            {
                  conn = new MySqlConnection(ConnectionString);
                MySqlCommand command = new MySqlCommand();
                PrepareCommand(command, conn, cmdText, parameters);
                MySqlDataReader mySqlDataReader = command.ExecuteReader();
                return mySqlDataReader;
            }
        }

然后再如此读出数据

        /// <summary>
        /// Query FileInformationModel entity list by FileInformationModel entity
        /// </summary>
        /// <param name="entity">FileInformationModel entity</param>
        /// <returns>FileInformationModel entity list</returns>
        public List<FileInformationModel> Query(FileInformationModel entity)
        {
           DbConnection conn;
            var result =
                ConvertDataReaderToList(DBHelp.ExecuteReader(Constants.spSelectFileInformationByCondition,
                                                             GetParameters(entity),out conn));
           ContentHelp.CloseConnection(conn);
           return result;
        }

        /// <summary>
        /// Convert data reader to FileInformationModel entity list
        /// </summary>
        /// <param name="reader">Db DataReader</param>
        /// <returns>FileInformationModel entity list</returns>
        private List<FileInformationModel> ConvertDataReaderToList(DbDataReader reader)
        {
            List<FileInformationModel> fileInformationList = new List<FileInformationModel>();
            using (reader)
            {
                while (reader.Read())
                {
                    FileInformationModel entity = new FileInformationModel();
                    entity.ContentType = ContentHelp.GetObjectToString(reader["ConntentType"]);
                    entity.ContentOwner = ContentHelp.GetObjectToString(reader["ContentOwner"]);
                    entity.CreateTime = ContentHelp.GetObjectToDateTime(reader["CreateTime"]);
                    entity.FileAccessControl = ContentHelp.GetObjectToString(reader["FileAccessControl"]);
                    entity.FileFrom = ContentHelp.GetObjectToString(reader["FileFrom"]);
                    if (ContentHelp.GetObjectToString(reader["IsNew"]) != null)
                        entity.IsNew = Convert.ToBoolean(ContentHelp.GetObjectToInt(reader["IsNew"]));
                    entity.FileName = ContentHelp.GetObjectToString(reader["FileName"]);
                    entity.FileSaveType = ContentHelp.GetObjectToInt(reader["FileSaveType"]);
                    entity.FileUrl = ContentHelp.GetObjectToString(reader["FileUrl"]);
                    entity.FileID = ContentHelp.GetObjectToString(reader["FileID"]);
                    entity.LastAccessTime = ContentHelp.GetObjectToDateTime(reader["LastAccessTime"]);
                    entity.ModifyTime = ContentHelp.GetObjectToDateTime(reader["ModifyTime"]);
                    entity.Version = ContentHelp.GetObjectToInt(reader["Version"]);
                    fileInformationList.Add(entity);
                }
            }
            return fileInformationList;
        }

利用反射后,一切变得很容易.

        /// <summary>
        /// Execute reader by store procedure and parameter list
        /// </summary>
        /// <param name="cmdText">store procedure</param>
        /// <param name="parameters">parameter list</param>
        /// <returns>data reader</returns> 
        public List<T> ReadEntityList<T>(string cmdText, List<DbParameter> parameters) where T : new()
        {
            lock (lockObject)
            {
                using (MySqlConnection conn = new MySqlConnection(ConnectionString))
                {
                    using (MySqlCommand command = new MySqlCommand())
                    {
                        PrepareCommand(command, conn, cmdText, parameters);
                        MySqlDataReader mySqlDataReader = command.ExecuteReader();
                        return ReadEntityListByReader<T>(mySqlDataReader);
                    }
                }
            }
        }

        /// <summary>
        /// Read entity list by reader
        /// </summary>
        /// <typeparam name="T">entity</typeparam>
        /// <param name="reader">data reader</param>
        /// <returns>entity</returns>
        private List<T> ReadEntityListByReader<T>(MySqlDataReader reader) where T : new()
        {
            List<T> listT = new List<T>();
            using (reader)
            {
                while (reader.Read())
                {
                    T inst = new T();
                    foreach (var pi in typeof (T).GetProperties(BindingFlags.Instance | BindingFlags.Public))
                    {
                        var obj = new object();
                        try
                        {
                            obj = reader[pi.Name];
                        }
                        catch (Exception ex)
                        {
                            continue;
                        }

                        if (obj == DBNull.Value || obj == null)
                            continue;
                        var si = pi.GetSetMethod();
                        if (si == null)
                            continue;
                        pi.SetValue(inst, obj, null);
                    }
                    listT.Add(inst);
                }
            }
            return listT;
        }

然后再这样取出来

        /// <summary>
        /// Query FileInformationModel entity list by FileInformationModel entity
        /// </summary>
        /// <param name="entity">FileInformationModel entity</param>
        /// <returns>FileInformationModel entity list</returns>
        public List<FileInformationModel> Query(FileInformationModel entity)
        {
            return DBHelp.ReadEntityList<FileInformationModel>(Constants.spSelectFileInformationByCondition,
                                                               GetParameters(entity));
        }

用好反射,让Coding变得更容易.

欢迎各位参与讨论，如果觉得对你有帮助，请点击    推荐下，万分谢谢.

作者：spring yang

出处：http://www.cnblogs.com/springyangwc/

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