Question

我有一个只有一个按钮的简单QWidgets应用程序。这是标题

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "Windows.h"
//#include "Winuser.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:
    void on_pushButton_clicked();

private:
    Ui::MainWindow *ui;
    bool changed;
};

#endif // MAINWINDOW_H

实施

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    changed = false;
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_clicked()
{
    if (!changed){
//        DEVMODE *dm = new DEVMODE();
//        EnumDisplaySettings(NULL,ENUM_CURRENT_SETTINGS,dm);
//        dm->dmPelsWidth = (unsigned long) 1024;
//        dm->dmPelsHeight = (unsigned long) 768;
//        ChangeDisplaySettings(dm,CDS_FULLSCREEN);
        DEVMODE desiredMode = { 0 };
        desiredMode.dmSize = sizeof(DEVMODE);
        desiredMode.dmPelsWidth = 1024;
        desiredMode.dmPelsHeight = 768;
        desiredMode.dmFields = DM_PELSHEIGHT | DM_PELSWIDTH;
        LONG res = ChangeDisplaySettings(&desiredMode,CDS_UPDATEREGISTRY | CDS_GLOBAL | CDS_RESET );
    }
    else{
        ChangeDisplaySettings(NULL,0);
    }

    changed = !changed;
}

我的.pro文件

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = ChangeResolution
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

LIBS += -luser32

SOURCES += \
        main.cpp \
        mainwindow.cpp

HEADERS += \
        mainwindow.h

FORMS += \
        mainwindow.ui

我需要开发一个需要更改显示分辨率的应用程序，仅在显示某些图像时，才能达到1024x768，然后再恢复正常。为了测试如何做到这一点，我正在尝试上面的代码，我在这里或者发现。但是，在尝试编译上面的代码时，我收到以下链接错误：

mainwindow.obj:-1: error: LNK2019: unresolved external symbol __imp_ChangeDisplaySettingsW referenced in function "private: void __cdecl MainWindow::on_pushButton_clicked(void)" (?on_pushButton_clicked@MainWindow@@AEAAXXZ)

根据我的研究，这似乎与编译器没有找到lib有关，这就是为什么我将LIBS行添加到.pro文件中，但没有任何改变。

我的项目设置表明我使用的是Qt 5.10.0 MSVC2017 64位编译器。

有关如何编译的任何帮助吗？

无法编译简单的Qt App来链接Windows user32 lib

0 个答案: