Qt开发之获取电脑磁盘容量_C/C++

项目中用到了监测某磁盘（如：C盘、D盘等）的总容量和可用容量，查了一下，发现其实挺简单，调用一个Windows自带的API：GetDiskFreeSpaceEx( ... )就可以解决。用Qt做了一个测试例子，如下所示。

另：测试发现，如果给定路径不存在（如程序中"F:\"），则获取不到信息；通常给定用以获取磁盘容量信息的路径为“C:\”、"D:\"等，但给定已存在路径（如程序中"D:\Test"），同样可以获取到该路径所属信息。

示例代码：

				?

									/*main.cpp*/

									#include "acquirediskspace.h"

									#include <QtWidgets/QApplication>

									int main(int argc, char *argv[])

									{

									    QApplication a(argc, argv);

									    AcquireDiskSpace w;

									    w.show();

									    return a.exec();

									}

				?

									/*acquirediskspace.h */

									#ifndef ACQUIREDISKSPACE_H

									#define ACQUIREDISKSPACE_H

									#include <QDialog>

									class QLineEdit;

									class AcquireDiskSpace : public QDialog

									{

									    Q_OBJECT

									public:

									    AcquireDiskSpace( QWidget *parent = 0 );

									    ~AcquireDiskSpace();

									protected slots:

									    void slotDiskChanged( const QString& );

									private:

									    void GetDiskSpace( QString strDisk, double& dTotalBytes, double& dFreeBytes );

									private:

									    QLineEdit* m_pEdtTotalSpace;

									    QLineEdit* m_pEdtFreeSpace;

									};

									#endif // ACQUIREDISKSPACE_H

				?

									/*acquirediskspace.cpp */

									#include "acquirediskspace.h"

									#include <QLabel>

									#include <QLineEdit>

									#include <QPushButton>

									#include <QComboBox>

									#include <QGridLayout>

									#include <QMessageBox>

									#include "windows.h"

									AcquireDiskSpace::AcquireDiskSpace( QWidget *parent )

									    : QDialog( parent )

									{

									    setWindowFlags( Qt::WindowTitleHint );

									    resize( 400, 400 );

									    setStyleSheet( "QDialog{background:white;}" );

									    m_pEdtTotalSpace = new QLineEdit;

									    m_pEdtTotalSpace->setEnabled( false );

									    m_pEdtTotalSpace->setMinimumHeight( 30 );

									    m_pEdtFreeSpace = new QLineEdit;

									    m_pEdtFreeSpace->setEnabled( false );

									    m_pEdtFreeSpace->setMinimumHeight( 30 );

									    //Disk

									    QComboBox* pCmbDisk = new QComboBox;

									    pCmbDisk->addItem( "C:/" );

									    pCmbDisk->addItem( "D:/Test" );

									    pCmbDisk->addItem( "E:/" );

									    pCmbDisk->addItem( "F:/" );

									    pCmbDisk->addItem( "G:/" );

									    pCmbDisk->setMinimumHeight( 30 );

									    //Button

									    QPushButton* pBtnOK = new QPushButton( "OK" );

									    pBtnOK->setMinimumHeight( 30 );

									    QHBoxLayout* pBtnLayout = new QHBoxLayout;

									    pBtnLayout->addWidget( pBtnOK );

									    //MainLayout

									    QGridLayout* pMainLayout = new QGridLayout;

									    pMainLayout->addWidget( new QLabel( "Total:" ), 0, 0, Qt::AlignRight );

									    pMainLayout->addWidget( m_pEdtTotalSpace, 0, 1 );

									    pMainLayout->addWidget( new QLabel( "GB" ), 0, 2 );

									    pMainLayout->addWidget( new QLabel( "Free:" ), 1, 0, Qt::AlignRight );

									    pMainLayout->addWidget( m_pEdtFreeSpace, 1, 1 );

									    pMainLayout->addWidget( new QLabel( "GB" ), 1, 2 );

									    pMainLayout->addWidget( new QLabel( "Disk:" ), 2, 0, Qt::AlignRight );

									    pMainLayout->addWidget( pCmbDisk, 2, 1 );

									    pMainLayout->addLayout( pBtnLayout, 3, 1 );

									    setLayout( pMainLayout );

									    //connects

									    connect( pCmbDisk, SIGNAL( currentIndexChanged( const QString& ) ), this, SLOT( slotDiskChanged( const QString& ) ) );

									    connect( pBtnOK, SIGNAL( clicked() ), this, SLOT( accept() ) );

									    //Init

									    QString strDisk = pCmbDisk->currentText();

									    slotDiskChanged( strDisk );

									}

									AcquireDiskSpace::~AcquireDiskSpace()

									{

									}

									void AcquireDiskSpace::slotDiskChanged( const QString& strDisk )

									{

									    double dTotalBytes, dFreeBytes;

									    GetDiskSpace( strDisk, dTotalBytes, dFreeBytes );

									    m_pEdtTotalSpace->setText( QString::number( dTotalBytes, 'f', 3 ) );

									    m_pEdtFreeSpace->setText( QString::number( dFreeBytes, 'f', 3 ) );

									}

									void AcquireDiskSpace::GetDiskSpace( QString strDisk, double& dTotalBytes, double& dFreeBytes )

									{

									    LPCWSTR lpcwstrDriver = (LPCWSTR)strDisk.utf16();

									    ULARGE_INTEGER lFreeBytesAvailable, lTotalBytesTemp, lTotalFreeBytes;

									    if( !GetDiskFreeSpaceEx( lpcwstrDriver, &lFreeBytesAvailable, &lTotalBytesTemp, &lTotalFreeBytes ) )

									    {

									        QMessageBox::warning( 0, "Warning", "Acquire Disk Space Failed !" );

									        dTotalBytes = -1;

									        dFreeBytes = -1;

									        return;

									    }

									    //unit : GB

									    dTotalBytes = lTotalBytesTemp.QuadPart / 1024.0 / 1024 / 1024;

									    dFreeBytes = lTotalFreeBytes.QuadPart / 1024.0 / 1024 / 1024;

									}