1.将图片转为字节流

 public byte[] SaveImage(String path)//输入图片路径
        {
            FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read); //将图片以文件流的形式进行保存
            BinaryReader br = new BinaryReader(fs);
            byte[] imgBytesIn = br.ReadBytes((int)fs.Length);  //将流读入到字节数组中
            return imgBytesIn;
        }

2.将图片上传到数据库的Blob字段

private void UpLoadEanPic()
        {
            string picFile = "";
            OpenFileDialog dialog = new OpenFileDialog();
            dialog.Multiselect = false;//该值确定是否可以选择多个文件
            dialog.Title = "请选择需要存储到" + custCode + "中的EAN图片";
            dialog.Filter = "图片文件(*.jpg,*.gif,*.bmp,*.png)|*.jpg;*.gif;*.bmp;*.png";
            if (dialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                 picFile = dialog.FileName;
            }
            else
            {
                return;
            }
            byte[] picBytes = SaveImage(picFile);
            string sqlInsertPic = string.Format(@"update cust_code_info set
ean_pic=:picBytes
where cust_code=:custCode");
            OracleParameter op1 = new OracleParameter("picBytes", OracleType.Blob);
            op1.Value = picBytes;
            OracleParameter op2 = new OracleParameter("custCode", OracleType.VarChar);
            op2.Value = custCode;
            IDataParameter[] parameters = new IDataParameter[]{op1,op2};
            int sqlRe = 0;
            try
            {
                sqlRe = DBManager.DBHelp.Instance().ExecuteSql(sqlInsertPic, parameters);
            }
            catch(Exception ex)
            {
                MessageBox.Show("上传失败！"+ex.Message);
                return;
            }
            if (sqlRe == 0)
            {
                MessageBox.Show("上传失败！请检查数据并重试！");
                return;
            }
            else
            {
                MessageBox.Show("上传成功！");
                btn_query_Click(null, null);
            }
        }

3.将blob字段转为image,即下载图片

  private void btn_DownLoadEanPic_Click(object sender, EventArgs e)
        {
            string custCode = dataGridView1.CurrentRow.Cells["客户料号"].Value.ToString();
            FolderBrowserDialog dialog = new FolderBrowserDialog();
            dialog.Description = "请选择文件路径";

            if (dialog.ShowDialog() == DialogResult.OK)
            {
                string foldPath = dialog.SelectedPath;
                string sqlGetEanPic = string.Format(@"SELECT
                                                        ean_pic
                                                        FROM
                                                            cust_code_info where cust_code='{0}'", custCode);
                object reader = DBManager.DBHelp.Instance().GetDataSingle(sqlGetEanPic);
                if (reader == Convert.DBNull)
                {
                    MessageBox.Show("未上传EAN图片，请检查！");
                    return;
                }
                byte[] bytes = (byte[])reader;//读到的内容转化成字节流
                System.IO.MemoryStream ms = new MemoryStream(bytes);//创建流
                System.Drawing.Image img = System.Drawing.Image.FromStream(ms);//从流中创建image对象
                string format = GetImageFormat(img);
                if (string.IsNullOrEmpty(format))
                {
                    MessageBox.Show("文件格式已经损坏，请重新上传！");
                    return;
                }
                img.Save(foldPath + "\\" + custCode + "图片" + format);//将image对象保存成图片存入指定位置
                MessageBox.Show("保存成功！");
            }
            else
            {
                return;
            }
        }

4.获取image图片格式

 private string GetImageFormat(Image _img)
        {
            string format;
            if (_img.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Jpeg))
            {
                format = ".jpg";
                return format;
            }
            if (_img.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Gif))
            {
                format = ".gif";
                return format;
            }
            if (_img.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Png))
            {
                format = ".png";
                return format;
            }
            if (_img.RawFormat.Equals(System.Drawing.Imaging.ImageFormat.Bmp))
            {
                format = ".bmp";
                return format;
            }
            format = string.Empty;
            return format;
        }

不断积累！