Qt/C++ 开源项目 学生成绩管理系统（简易版）数据库常规使用与文本导入、导出使用（源码工程联系博主）

void DatabaseManager::addStudent(const Student& student) {
    QSqlQuery query(db);
    query.prepare("INSERT INTO students (name, score) VALUES (:name, :score)");
    query.bindValue(":name", student.getName());
    query.bindValue(":score", student.getScore());
    query.exec();
}

void MainWindow::addStudent() {
    QString name = nameEdit->text();
    double score = scoreSpin->value();
    if (name.isEmpty() || score < 0) {
        QMessageBox::warning(this, "Input Error", "Invalid name or score.");
        return;
    }
    Student student(getNextStudentId(), name, score);
    studentManager.addStudent(student);
    refreshStudentTable();
    updateChart();
}

void MainWindow::searchStudents() {
    QString name = searchEdit->text();
    auto students = studentManager.findStudentsByName(name);
    refreshStudentTable(students);
    updateChart();
}

void MainWindow::exportData() {
    QString fileName = QFileDialog::getSaveFileName(this, tr("Save File"), "", tr("CSV (*.csv)"));
    if (fileName.isEmpty()) {
        return;
    }
    QFile file(fileName);
    if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
        QMessageBox::warning(this, tr("Error"), tr("Unable to open file"));
        return;
    }


    QTextStream stream(&file);
    QStringList strList;


    // 写入标题
    for (int c = 0; c < studentTable->horizontalHeader()->count(); ++c) {
        strList << "\"" + studentTable->model()->headerData(c, Qt::Horizontal).toString() + "\"";
    }
    stream << strList.join(",") << "\n";


    // 写入数据
    for (int r = 0; r < studentTable->rowCount(); ++r) {
        strList.clear();
        for (int c = 0; c < studentTable->columnCount(); ++c) {
            strList << "\"" + studentTable->item(r, c)->text() + "\"";
        }
        stream << strList.join(",") << "\n";
    }
    file.close();
}

QChart* MainWindow::createChart() {
    QBarSeries *series = new QBarSeries();
    QBarSet *set = new QBarSet(tc("及格线"));
    QStringList categories;


    QList<Student> students = studentManager.getAllStudents();
    for (const Student &student : students) {
        *set << student.getScore();  // 将分数添加到柱状图
        categories << student.getName();  // 将学生名字添加到类别中
    }
    series->append(set);


    QChart *chart = new QChart();
    chart->addSeries(series);
    chart->setTitle(tc("班级成绩柱状图"));
    chart->setAnimationOptions(QChart::SeriesAnimations);


    QBarCategoryAxis *axisX = new QBarCategoryAxis();
    axisX->append(categories);  // 设置类别为学生姓名
    chart->addAxis(axisX, Qt::AlignBottom);
    series->attachAxis(axisX);


    QValueAxis *axisY = new QValueAxis();
    axisY->setRange(0, 100);
    axisY->setTickInterval(10);
    chart->addAxis(axisY, Qt::AlignLeft);
    series->attachAxis(axisY);


    // 在 60 分位置绘制一条横线作为及格线
    QLineSeries *passLine = new QLineSeries();
    passLine->append(QPointF(-5, 60));
    passLine->append(QPointF(students.count(), 60)); // 覆盖整个 X 轴范围
    QPen pen(Qt::red, 2, Qt::DashLine); // 红色虚线
    passLine->setPen(pen);
    chart->addSeries(passLine);
    passLine->attachAxis(axisX);
    passLine->attachAxis(axisY);


    return chart;
}

void MainWindow::importData() {
    QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), "", tr("CSV (*.csv)"));
    if (fileName.isEmpty()) {
        return;
    }


    QFile file(fileName);
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        QMessageBox::warning(this, tr("Error"), tr("Unable to open file"));
        return;
    }


    QTextStream stream(&file);
    // 忽略第一行标题
    if (!stream.atEnd()) {
        stream.readLine();
    }


    QSet<QString> existingNames;
for (const auto &student : studentManager.getAllStudents()) {
        existingNames.insert(student.getName());
    }
    int nextId = getNextStudentId();


    while (!stream.atEnd()) {
        QString line = stream.readLine();
        QStringList strList = line.split(",");
        if (strList.size() >= 3) {
            QString name = strList.at(1).trimmed().replace("\"", "");
            double score = strList.at(2).trimmed().replace("\"", "").toDouble();


            // 仅添加不存在的新名字
            if (!existingNames.contains(name)) {
                Student student(nextId++, name, score);
                studentManager.addStudent(student);
                existingNames.insert(name);
            }
        }
    }


    file.close();
    refreshStudentTable();  // 更新表格
    updateChart();          // 更新图表
}