conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = "select * from t_import";
                    SqlDataReader sdr = cmd.ExecuteReader();
                    using (FileStream fs = File.Create(saveFileDialog1.FileName))
                    {
                        using (StreamWriter sw = new StreamWriter(fs))
                        {
                            while (sdr.Read())
                            {
                                string name = sdr.GetString(sdr.GetOrdinal("name"));
                                int age = sdr.GetInt32(sdr.GetOrdinal("age"));
                                sw.WriteLine("{0}-{1}", name, age);
                            }
                        }
                    }
                }

===============================================
以上代码中感觉这句话不要也能行
using (FileStream fs = File.Create(saveFileDialog1.FileName))
只要把using (StreamWriter sw = new StreamWriter(fs))这句话改成
using (StreamWriter sw = new StreamWriter(saveFileDialog1.FileName))
也行，
小弟深感迷惑，请高手指点迷津，感激不尽