Qt開發之獲取電腦磁盤容量

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項目中用到瞭監測某磁盤（如：C盤、D盤等）的總容量和可用容量，查瞭一下，發現其實挺簡單，調用一個Windows自帶的API：GetDiskFreeSpaceEx( … )就可以解決。用Qt做瞭一個測試例子，如下所示。

另：測試發現，如果給定路徑不存在（如程序中"F:\"），則獲取不到信息；通常給定用以獲取磁盤容量信息的路徑為“C:\”、"D:\"等，但給定已存在路徑（如程序中"D:\Test"），同樣可以獲取到該路徑所屬信息。

示例代碼：

/*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;
}

結果如下：

(1)C盤：

(2)D盤：

(3)F盤（F盤實際上並不存在，故獲取不到，給瞭默認值-1,-1）

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