using?System;
using?System.Collections.Generic;
using?System.Linq;
using?System.Text;
using?System.Threading.Tasks;
using?System.Data.SqlClient;
using?System.Data;
using?System.ComponentModel;
using?System.Drawing;
using?System.Windows.Forms;

namespace?KTVForms
{
????///?

????///?操作數據庫類
????///?

????class?DBHelper
????{
????????public?string?conu?=?“server=.;?database=MyKTV;?uid=sa;?pwd=sa“;

????????private?SqlConnection?connection;

????????///?

????????///?數據庫連接對象屬性
????????///?

????????public?SqlConnection?Connection
????????{
????????????get
????????????{
????????????????if?（connection?==?null）
????????????????{
????????????????????connection?=?new?SqlConnection（conu）;
????????????????}
????????????????return?connection;
????????????}
????????}
????????///?

????????///?打開數據庫
????????///?

????????public?void?OpenConnection（）
????????{
????????????if?（connection.State?==?ConnectionState.Closed）
????????????{
????????????????connection.Open（）;
????????????}?if?（connection.State?==?ConnectionState.Broken）
????????????{
????????????????connection.Close（）;
????????????????connection.Open（）;
????????????}
????????}
????????///?

????????///?關閉數據庫
????????///?

????????public?void?CloseConnection（）
????????{
????????????if?（connection.State?==?ConnectionState.Open?||?connection.State?==?ConnectionState.Broken）
????????????{
????????????????connection.Close（）;
????????????}
????????}



????????///?

????????///增\刪\改，返回受影響行
????????///?

????????///?
????????public?int?name（string?sql）
????????{
????????????SqlConnection?com?=?new?SqlConnection（conu）;

????????????int?i?=?0;

????????????SqlCommand?wo?=?new?SqlCommand（sql?Connection）;

????????????try
????????????{
????????????????OpenConnection（）;

????????????????i?=?wo.ExecuteNonQuery（）;



????????????}
????????????catch?（Exception?en）
????????????{

????????????????MessageBox.Show（en.Message）;
????????????}

????????????finally
????????????{
????????????????CloseConnection（）;
????????????}
????????????return?i;
????????}





????????///?

????????///?返回整型
????????///?

????????///?
????????///?
????????public?object?select1（string?sql）
????????{
????????????object?name?=?null;
????????????SqlCommand?wo?=?new?SqlCommand（sql?Connection）;

????????????try
????????????{
????????????????OpenConnection（）;

????????????????name?=?wo.ExecuteScalar（）;



????????????}
????????????catch?（Exception?en）
????????????{

????????????????MessageBox.Show（en.Message）;
????????????}
????????????finally
????????????{
????????????????CloseConnection（）;
????????????}
????????????return?name;
????????}





????????///?

????????///?返回單個返回值
????????///?

????????///?