前言

这篇博客针对<<VS+Qt+C++银行排队叫号系统>>编写代码，带用户登录，管理员登录，增删改查，代码整洁，规则，易读。学习与应用推荐首选。

文章目录

一、所需工具软件

二、使用步骤

1. 引入库

2. 代码实现

3. 运行结果

三、在线协助

一、所需工具软件

1. VS, Qt

2. C++

二、使用步骤

1.引入库

#pragma once

#include <QtWidgets/QMainWindow>
#include "ui_AdminManager.h"


#include <QWidget>

#include <QtSql/QSqlDatabase>
#include <QtSql/QSqlError>
#include <QtSql/QtSql>

2. 代码实现

代码如下:

#if defined(_MSC_VER) && (_MSC_VER >= 1600)
#pragma execution_character_set("utf-8")
#endif

#include "UserManager.h"


#include<iostream>
using namespace std;

UserManager::UserManager(QWidget *parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);


    QObject::connect(ui.pushButton_4, SIGNAL(clicked()), this, SLOT(on_findButton_clicked()));
    QObject::connect(ui.pushButton, SIGNAL(clicked()), this, SLOT(on_addButton_clicked()));
    ui.pushButton_4->setVisible(true);

    //ui.tableWidget->setAlternatingRowColors(true); // 隔行变色
    //ui.tableWidget->setPalette(QPalette(QColor(220, 250, 255)));//参数还可写成QPalette(Qt::blue)
    
    //背景色
    ui.tableWidget->setStyleSheet("QTableView::Item{background-color:green}");



    db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("information.db");
    // 2. 打开数据库
    if (!db.open())
        qDebug() << "open error" << db.lastError();

    QSqlQuery query;
    //判断information是否已存在，存在则不创建，不存在这创建
    QString sqlFindTableName = QString("select count(*) from informationTable where type = 'table' and name='%1'").arg("informationTable");  //功能同上

    if (!query.exec(sqlFindTableName))
        qDebug() << "findTable error" << db.lastError();
    bool isTableExist = query.exec(sqlFindTableName);
    qDebug() << isTableExist;
    if (!isTableExist)
    {
        //表  字段有id name class
        QString sqlCreate = QString("create table informationTable(id integer primary key autoincrement,"
            "name varchar(20),"
            "gender varchar(20),"
            "age varchar(20),"
            "class int);");
        if (!query.exec(sqlCreate))
            qDebug() << "create table error" << db.lastError();
    }

}

//显示所有
void UserManager::on_findButton_clicked()
{
    std::cout << "test_ " << std::endl;

    if (true == db.open())
    {
        QSqlQuery query(db);
        if (query.exec("select * from informationTable"))
        {
            ui.tableWidget->clearContents();
            ui.tableWidget->setRowCount(0);

            while (query.next())
            {
                int rowCount = ui.tableWidget->rowCount();
                ui.tableWidget->insertRow(rowCount);

                QTableWidgetItem* columnItem0 = new QTableWidgetItem(
                    query.value(0).toString());
                QTableWidgetItem* columnItem1 = new QTableWidgetItem(
                    query.value(1).toString());
                QTableWidgetItem* columnItem2 = new QTableWidgetItem(
                    query.value(2).toString());
                QTableWidgetItem* columnItem3= new QTableWidgetItem(
                    query.value(3).toString());
                QTableWidgetItem* columnItem4 = new QTableWidgetItem(
                    query.value(4).toString());

                ui.tableWidget->setItem(rowCount, 0, columnItem0);
                ui.tableWidget->setItem(rowCount, 1, columnItem1);
                ui.tableWidget->setItem(rowCount, 2, columnItem2);
                ui.tableWidget->setItem(rowCount, 3, columnItem3);
                ui.tableWidget->setItem(rowCount, 4, columnItem4);

            }
        }
    }

}


//添加
void UserManager::on_addButton_clicked()
{
    QString IDEd = ui.idLineEdit->text();
    if (IDEd != "")
    {
        QString status = ui.comboBox->currentText();;
        //将通过数据库接口的访问，将数据插入到数据库中
        QSqlQuery query;
        //QString sqlInert = QString("insert into informationTable(name, class)" "values('%1', %2)").arg(nameEd).arg(classNum);
        QString sqlInert = QString("insert into informationTable(ID, name)" "values('%1','%2')").arg(IDEd, status);
        if (!query.exec(sqlInert))
            qDebug() << "insert data error" << db.lastError();
        on_findButton_clicked();
    }
}