把ORACLE数据库中的bblob字段导成图片（C#实现）

string myOraclestr = "Data Source=" + this.textBox1.Text + ";User Id=" + this.textBox2.Text + ";Password=" + this.textBox3.Text + ";";
OracleConnection conn = new OracleConnection(myOraclestr);
OracleCommand cmd = conn.CreateCommand();
conn.Open();
cmd.CommandText = "select r.sfzhm,p.txsj from hdds_obj_0000r010000 r,hdds_obj_0000picture p where r.zxbs is null and r.photoid is not null and r.photoid=p.serial_no";
OracleDataReader dr = cmd.ExecuteReader();
int i=0;
while (dr.Read())
{
     try
     {
          byte[] tempByte = (byte[])dr[1];
          FileStream fs = new FileStream(this.textBox4.Text + "\\" + dr[0].ToString() + ".jpg", FileMode.Create);
          fs.Write(tempByte, 0, tempByte.Length);
          fs.Close();
          Application.DoEvents();
          this.label5.Text = (i++).ToString();;
       }
       catch (Exception ex)
       {
            MessageBox.Show(ex.Message);
        }
}
dr.Close();
conn.Close();
MessageBox.Show("导出完成！！！");