c++ - 不可用的 Ui 属性

Question

我一直在尝试使用 Qt Creator 在 C++ 中实现一个项目 – 这是基于 Qt Creator 5.4.1 的 Qt Creator 3.3.1(开源)。我使用 Ubuntu 14.04。

我发现了一些主题与我想要创建的内容相似的教程，因此我一直在研究代码并尝试使其适合我的需要。这是 GUI 项目。我也一直在处理这个项目来学习更多的 C++，OOP。我做了2个表格。

该项目目前由 3 个类组成。一个类包括一个表格来收集一些关于人的信息——它有效。主类包括 QtableWidget 以在表中显示有关数据库中人员的详细信息，我还实现了查找人员的方法(也在主类中)，按姓氏搜索——在表格中我使用 QlineEdit 来完成。

但是我需要另一个表格来编辑关于严格的人的信息。我决定在另一个类中实现表单来编辑信息。问题出现了，因为要编辑关于严格的人的信息，我需要能够读取我在 QlineEdit 的空白处键入的内容，然后使用此信息在数据库中进行搜索(来自 QlineEdit which以主类的形式包含)。

问题是，在第二类(编辑)中，当我在构造函数中使用构造时:QString Surname = ui->name_of_the_gap->text(); - 其中 ”name_of_the_gap” 是间隙的名称，其中包括我想使用的姓氏，但它恰好不适用于此 UI(类中的 ui，其中有此表单可编辑信息)。

我尝试过使用继承，但没有一个有效。我可以请你指导我/指出我应该怎么做/我应该改变什么吗？

下面我将向您展示代码片段:

地址记录.h

#ifndef ADDRECORD_H
#define ADDRECORD_H
#include <QDialog>
#include <QtSql/qsqldatabase.h>
#include <QtSql/QSqlError>
#include <QtSql/QSql>
#include <QtSql/QSqlDatabase>
#include <QtSql/QSqlDriver>
#include <QtSql/qsqldriver.h>
#include <QtSql/QSqlDriverPlugin>
#include <QtSql/qsqldriverplugin.h>
#include <QSqlQuery>
#include <QDebug>
#include <QString>
#include <QMessageBox>
namespace Ui {
class AddRecord;
}
class AddRecord : public QDialog
{
    Q_OBJECT
public:
    explicit AddRecord(QWidget *parent = 0);
    ~AddRecord();
private slots:
    void on_btnQuit_clicked();
    void on_btnAdd_clicked();
private:
    Ui::AddRecord *ui;
};

 **/*addrecord.h*/**

编辑记录.h

#ifndef EDITRECORD_H
#define EDITRECORD_H
#include <QDialog>
//#include "mainwindow.h"
//#include "addrecord.h"
#include <QLineEdit>
namespace Ui {
class EditRecord;
}
class EditRecord : public QDialog
//class EditRecord :  public MainWindow
{
    Q_OBJECT
public:
    explicit EditRecord(QWidget *parent = 0);
    ~EditRecord();
    Ui::EditRecord *eui;
private slots:
    void on_btnQuit_clicked();
private:
    //Ui::EditRecord *ui;
    //Ui::EditRecord *ui;
    //Ui::MainWindow *mui;
    QLineEdit *searchSurnameEdit;
};
#endif // EDITRECORD_H

主窗口.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include "addrecord.h"
#include "editrecord.h"
#include <QMainWindow>
#include <QtCore>
#include <QtGui>
#include <QSql>
#include <QtSql/qsqldatabase.h>
#include <QtSql/QSqlError>
#include <QtSql/QSql>
#include <QtSql/QSqlDatabase>
#include <QtSql/QSqlDriver>
#include <QtSql/qsqldriver.h>
#include <QtSql/QSqlDriverPlugin>
#include <QtSql/qsqldriverplugin.h>
#include <QSqlQuery>
#include <QDebug>
#include <QSqlRecord>
#include <QSqlTableModel>
#include <QModelIndexList>
#include <QTableView>
#include "editrecord.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
    Ui::MainWindow *ui;
    void fillTable();
private slots:
    void on_tableWidget_cellChanged(int row, int column);
    void on_btnQuit_clicked();
    void on_btnAdd_clicked();
    void on_btnSearchSurname_clicked();
    void on_btnEditData_clicked();
private:
    bool loading;
    //Ui::MainWindow *ui;
    QStandardItemModel *model;
    QSqlDatabase *myDb;
    QSqlTableModel *empmodel;
    QItemSelectionModel *selection;
    QTableView *view;
    QModelIndexList indexes;
    QSqlQuery *q;
    //EditRecord *editrecord;
};
#endif // MAINWINDOW_H

地址记录.cpp

#include "addrecord.h"
#include "ui_addrecord.h"
AddRecord::AddRecord(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::AddRecord)
{
    ui->setupUi(this);
}
AddRecord::~AddRecord()
{
    delete ui;
}
void AddRecord::on_btnQuit_clicked()
{
    this->close();
}
void AddRecord::on_btnAdd_clicked()
{
    QSqlDatabase db1 = QSqlDatabase::addDatabase("QMYSQL");
    db1.setHostName("localhost");
    db1.setDatabaseName("dbname");
    db1.setUserName("user");
    db1.setPassword(„passwd");
    db1.open();
    QString gkUserid,name,second_name,surname,date_of_birth,NIP,street,postalcode,desc,telefhone,mobile_phone,email,sex,city;
    name = ui->nameEdit->text();
    second_name = ui->secondNameEdit->text();
    surname = ui->surnameEdit->text();
    date_of_birth = ui->dateofBirthEdit->text();
    NIP = ui->nipEdit->text();
    street = ui->streetEdit->text();
    postalcode = ui->postalCodeEdit->text();
    desc = ui->descEdit->acceptRichText();
    telefhone = ui->telephoneEdit->text();
    mobile_phone = ui->mobilePhoneEdit->text();
    email = ui->eMailEdit->text();
    sex = ui->sexEdit->text();
    city = ui->cityEdit->text();
    if(!db1.open()){
        qDebug()<<"Failed to open database";
        return;
    } else {
        qDebug()<<"OK";
    }
    QSqlQuery query("qt_mysql");
    query.prepare("INSERT INTO gkUsers VALUES (:gkUserid,:name,:second_name,:surname,:date_of_birth,:NIP,:street,:postal_code,:desc,:telephone,:mobile_phone,:email,:sex,:city)");
    query.bindValue(":name",name);
    query.bindValue(":second_name",second_name);
    query.bindValue(":surname",surname);
    query.bindValue(":date_of_birth",date_of_birth);
    query.bindValue(":NIP",NIP);
    query.bindValue(":street",street);
    query.bindValue(":postal_code",postal_code);
    query.bindValue(":desc",desc);
    query.bindValue(":telephone",telephone);
    query.bindValue(":mobile_phone",mobile_phone);
    query.bindValue(":email",email);
    query.bindValue(":sex",sex);
    query.bindValue(":city",city);
    if(query.exec()){
        QMessageBox::critical(this,tr("Save"),tr("Saved"));
        db1.close();
        ui->nameEdit->setText("");
        ui->secondNameEdit->setText("");
        ui->surnameEdit->setText("");
        ui->dateofbirthEdit->setText("");
        ui->nipEdit->setText("");
        ui->streetEdit->setText("");
        ui->postalCodeEdit->setText("");
        ui->descEdit->acceptRichText();
        ui->telephoneEdit->setText("");
        ui->mobilephoneEdit->setText("");
        ui->eMailEdit->setText("");
        ui->sexEdit->setText("");
        ui->cityEdit->setText("");
    } else {
        QMessageBox::critical(this,tr("Error"),query.lastError().text());
    }
}

编辑记录.cpp

#include "editrecord.h"
#include "ui_editrecord.h"
#include "mainwindow.h"
EditRecord::EditRecord(QWidget *parent):
        // MainWindow(),
       QDialog(parent),
    //eui(new Ui::EditRecord), MainWindow(parent)
       eui(new Ui::EditRecord)
{
    eui->setupUi(this);
    //ui->setupUi(mui->placeholder);
   // EditRecord(Ui::MainWindow *ui)
    //QString Surname = ui->szukajNazwiskoEdit->text();
   // eui->setupUi(ui.placeholder);
}
EditRecord::~EditRecord()
{
    delete eui;
}
void EditRecord::on_btnZamknij_clicked()
{
    this->close();
}

    **/*editrecord.cpp*/**


    **/*main.cpp*/** 

#include "mainwindow.h"
#include "editrecord.h"
#include <QApplication>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    EditRecord e; //added
    w.show();
    return a.exec();
}         

     **/*main.cpp*/** 


    **/*mainwindow.cpp*/**

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "addrecord.h"
#include <QSql>
#include <QtSql/qsqldatabase.h>
#include <QtSql/QSqlError>
#include <QtSql/QSql>
#include <QtSql/QSqlDatabase>
#include <QtSql/QSqlDriver>
#include <QtSql/qsqldriver.h>
#include <QtSql/QSqlDriverPlugin>
#include <QtSql/qsqldriverplugin.h>
#include <QSqlQuery>
#include <QString>
MainWindow::MainWindow(QWidget *parent) :    
     QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QSqlDatabase myDb = QSqlDatabase::addDatabase("QMYSQL");
    myDb.setHostName("localhost");
    myDb.setDatabaseName("db");
    myDb.setUserName("user");
    myDb.setPassword("passwd");
    myDb.open();
    qDebug()<<myDb.open();
    ui->tableWidget->hideColumn(0);
    fillTable();
}
MainWindow::~MainWindow()
{
    delete ui;
}
void MainWindow::fillTable()
{
    loading = true;
    int num_rows, r, c;
    //QSqlQuery q(myDb);
    QSqlQuery q;
    //get the number of rows
    if(!q.exec("SELECT count(gkUserid) as num_rows FROM gkUsers")) qDebug()<< q.lastError().text();
    q.first();
    num_rows = q.value(0).toInt();
    ui->tableWidget->setRowCount(num_rows);
    ui->tableWidget->setMaximumWidth(1700);
    ui->tableWidget->setMaximumHeight(300);
    if(!q.exec("SELECT gkUserid, name, second_name, surname, date_of_birth, NIP, street, postalcode, desc, telephone, mobile_phone, email, sex, city FROM gkUsers ORDER BY gkUserid")) qDebug() << q.lastError().text();
    for(r = 0, q.first(); q.isValid(); q.next(), ++r)
    {
       //for(c = 0; c < q.numRowsAffected(); ++c)
       for(c = 0; c < 14; ++c)
       {
           ui->tableWidget->setItem(r,c, new QTableWidgetItem(q.value(c).toString()));
       }
    }
  loading = false;
}
void MainWindow::on_tableWidget_cellChanged(int row, int column)
{
    //int id = ui->tableWidget->item(row, 0)->text().toInt();
    if (loading) return;
    QSqlQuery q;
    q.prepare("UPDATE gkUsers SET name = :i, second_name = :d_i, surname = :n, date_of_birth = :d_u, NIP = :N, street = :u, postal_code = :k, opis = :o, telephone = :t, mobile_phone = :t_k, email = :e, sex = :p, city = :m WHERE gkUserid = :gkUserid");
    q.bindValue(":i", ui->tableWidget->item(row, 1)->text());
    q.bindValue(":d_i",ui->tableWidget->item(row, 2)->text());
    q.bindValue(":n", ui->tableWidget->item(row, 3)->text());
    q.bindValue(":d_u", ui->tableWidget->item(row, 4)->text());
    q.bindValue(":N", ui->tableWidget->item(row, 5)->text());
    q.bindValue(":u", ui->tableWidget->item(row, 6)->text());
    q.bindValue(":k", ui->tableWidget->item(row, 7)->text());
    q.bindValue(":o", ui->tableWidget->item(row, 8)->text());
    q.bindValue(":t", ui->tableWidget->item(row, 9)->text());
    q.bindValue(":t_k", ui->tableWidget->item(row, 10)->text());
    q.bindValue(":e", ui->tableWidget->item(row, 11)->text());
    q.bindValue(":p", ui->tableWidget->item(row, 12)->text());
    q.bindValue(":m", ui->tableWidget->item(row, 13)->text());
    q.bindValue(":gkUserid", ui->tableWidget->item(row, 0)->text().toInt());
    if(!q.exec()) qDebug() << q.lastError().text();
    fillTable();
}
void MainWindow::on_btnQuit_clicked()
{
    this->close();
}
void MainWindow::on_btnAdd_clicked()
{
    //QMainWindow window;
    //AddRecord * addrecord = new AddRecord(this);
    AddRecord addrecord;
    addrecord.setModal(true);
    addrecord.exec();
}
void MainWindow::on_btnSearchSurname_clicked()
{
    QString Surname = ui->searchSurnameEdit->text();
    qDebug()<<Surname;
    QSqlDatabase myDb = QSqlDatabase::addDatabase("QMYSQL");
    myDb.setHostName("localhost");
    myDb.setDatabaseName("db");
    myDb.setUserName("user");
    myDb.setPassword("passwd");
    qDebug()<<myDb.open();
    if(!myDb.open()){
        qDebug()<<"There is no connection to DB";
        return;
    }
    QSqlQuery qry;
    if(qry.exec("SELECT gkUserid, name, second_name, surname, date_of_birth, NIP, street, postal_code, desc, telephone, mobile_phone, email, sex, city FROM gkUsers WHERE surname = \'" + Surname + "\'"))
    {
        if(qry.next()){
            QString msg1 = qry.value(1).toString();
            QString msg2 = qry.value(2).toString();
            QString msg3 = qry.value(3).toString();
            QString msg4 = qry.value(4).toString();
            QString msg5 = qry.value(5).toString();
            QString msg6 = qry.value(6).toString();
            QString msg7 = qry.value(7).toString();
            QString msg8 = qry.value(8).toString();
            QString msg9 = qry.value(9).toString();
            QString msg10 = qry.value(10).toString();
            QString msg11 = qry.value(11).toString();
            QString msg12 = qry.value(12).toString();
            QString msg13 = qry.value(13).toString();
            QString msg14 = qry.value(14).toString();
            QString msg15 = qry.value(15).toString();
            ui->nameEdit->setText(msg1);
            ui->surnameEdit->setText(msg3);
            ui->dateofbirthEdit->setText(msg4);
            ui->nipEdit->setText(msg5);
            ui->telEdit->setText(msg9);
            ui->sexEdit->setText(msg12);
            ui->mobileEdit->setText(msg10);
            ui->streetEdit->setText(msg5);
            ui->cityEdit->setText(msg13);
            ui->descEdit->setText(msg8);
            myDb.close();
        } else {
            qDebug()<<"Something went wrong";
        }
    }
}
void MainWindow::on_btnEditData_clicked()
{
    EditRecord editrecord;
    editrecord.setModal(true);
    editrecord.exec();
    //editrecord = new EditRecord(this);
    //editrecord->show();
}

我的代表.pro

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = MyDelegate
TEMPLATE = app

QT += sql

SOURCES += main.cpp\
        mainwindow.cpp \
    addrecord.cpp \
    editrecord.cpp

HEADERS  += mainwindow.h \
    addrecord.h \
    editrecord.h

FORMS    += mainwindow.ui \
    addrecord.ui \
    editrecord.ui \
    edit_record.ui          

Answer 1

这是因为每个类都有自己的 Ui，代表您为该表单而不是其他表单定义的特定 UI 元素。所以在 EditRecord 类中你不能访问 ui->name_of_the_gap，因为在 EditRecord 表单中没有定义这样的东西。它已为您的其他类定义的事实与此处无关，因为您无权访问它。

解决方案是在显示 EditRecord 之前获取您需要的任何信息(在您的情况下，是在 MainWindow 的 QLineEdit 中输入的文本) 然后将该值传递给 EditRecord。换句话说，当您可以访问它并传递该值时，您必须从 QLineEdit 获取值，而不是在您不能访问该 QLineEdit 时尝试访问该值。

为此，您必须将该值传递给 EditForm 的构造函数。你需要的改变是这样的:

//In editrecord.h:
explicit EditRecord(QString surname, QWidget *parent = 0);

//In editrecord.cpp:
EditRecord::EditRecord(QString surname, QWidget *parent):
    QDialog(parent),
    eui(new Ui::EditRecord)
{
    eui->setupUi(this);
    //Now you have access to 'surname'. Do whatever you need to do with it.
    //...
}

//In maitwindow.cpp:
void MainWindow::on_btnEditData_clicked()
{
    QString surname = ui->name_of_the_gap->text();
    EditRecord editrecord(surname);
    editrecord.setModal(true);
    editrecord.exec();
}

请注意，您也可以通过这种方式发送 ui，但它在 OOP 中被认为是错误的。