Qt开发之获取电脑磁盘容量
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：
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/*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();}1
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/*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_H1
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/*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;}结果如下：
(1)C盘：
(2)D盘：
(3)F盘（F盘实际上并不存在，故获取不到，给了默认值-1,-1）
