dataset 中将 将2进制数组列的数据 转换成文件 和 从文件中 转换到 dataset 方法

///将2进制数组转换成文件  
        /// </summary>
        /// <param name="psPath">路径+文本文件名字</param>
        /// <param name="ds">数据源</param>
        /// <param name="row">行号</param>
        /// <param name="col">列名称</param>
        private void tofilebyte(string psPath,DataSet ds,int row,string col)
        {
            FileStream fileStream = new FileStream(psPath , FileMode.OpenOrCreate, FileAccess.Write);
            BinaryWriter binaryWriter = new BinaryWriter(fileStream);     

            Byte[] byteBLOBData = new Byte[0];
            if(ds.Tables[0].Rows[row][col] != System.DBNull.Value)
                byteBLOBData = (Byte[])(ds.Tables[0].Rows[row][col]);
     
            binaryWriter.Write(byteBLOBData);
            binaryWriter.Flush();
            binaryWriter.Close();
            fileStream.Close(); 
        }

 //转换成2进制数组 导入到dataset 直接赋给 dataset 对应列类型System.Byte[]
        /// <summary>
        /// 根据路径从文本文件中 取数
        /// </summary>
        /// <param name="Filename">路径+表名称</param>
        /// <returns>Image类型数据</returns>
        public static byte[] GetFileBytes(string Filename)
        {
            if (Filename == "")
                return null;

            FileStream fileStream = new FileStream(Filename, FileMode.Open, FileAccess.Read);
            BinaryReader binaryReader = new BinaryReader(fileStream);

            byte[] fileBytes = binaryReader.ReadBytes((int)fileStream.Length);
            binaryReader.Close();
            fileStream.Close();

            return fileBytes;
        }