从数据库中把数据导出到txt文件（savefiledialog控件）

按上图所示布局

按上图所示布局数据库

导出数据按钮代码：

if (sfddata.ShowDialog() == DialogResult.OK) { using (SqlConnection conn = new SqlConnection()) { //计数器 int count = 0; conn.ConnectionString = @"Data Source=./SQLEXPRESS;AttachDBFilename=|DataDirectory|/persons.mdf;Integrated Security=True;User Instance=True"; conn.Open(); SqlCommand cmd = conn.CreateCommand(); cmd.CommandText = "select * from T_persons"; SqlDataReader reader = cmd.ExecuteReader(); while (reader.Read()) { string db_name = reader.GetString(reader.GetOrdinal("pname")); int db_scores = reader.GetInt32(reader.GetOrdinal("pscores")); File.AppendAllText(Path.GetFullPath(sfddata.FileName), db_name + "|" + db_scores + "/r/n"); count++; } MessageBox.Show(count + "行数据导出完成"); } } else { return; }