drvlistbox.cpp

WINDOWS下读取硬盘扇区的程序的源码 VC6.0下编译通过

// ==========================================================================
// DrvListBox.cpp : implementation file
// ==========================================================================

#include "stdafx.h"
#include "DrvListBox.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

// ==========================================================================
// Construction/Destruction
// ==========================================================================
CDrvListBox::CDrvListBox() :
  m_pDriveStrings( NULL ),
	m_pImageList( NULL )
	{
	}
CDrvListBox::~CDrvListBox()
	{
  // detach system image list before deleting it: otherwise when I delete the 
	// list I'd be deallocating the system-wide image list

	if( m_pImageList != NULL )
		{
		m_pImageList->Detach();
		delete m_pImageList;
		}

	// this should be safe since all pointers into that buffer are destroyed
	// at the "same" time

	if( m_pDriveStrings != NULL )
		delete[] m_pDriveStrings;
	}
// ==========================================================================
// Message Map
// ==========================================================================

BEGIN_MESSAGE_MAP(CDrvListBox, CComboBoxEx)
	//{{AFX_MSG_MAP(CDrvListBox)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

// ==========================================================================
// Load Items - collects all drive information and place it into the listbox,
// return number of items added to the list: a negative value is an error;
// ==========================================================================
int CDrvListBox::LoadItems( const bool bLargeIcons )
{
	if( m_pDriveStrings != NULL )
		return -1; // duplicate calls are not implemented

	// allocate buffer for the drive strings: GetLogicalDriveStrings will tell
	// me how much is needed (minus the trailing zero-byte)

	size_t lAllDriveStrings = GetLogicalDriveStrings( 0, NULL );

	_ASSERT( m_pDriveStrings == NULL );
		m_pDriveStrings = new _TCHAR[ lAllDriveStrings + sizeof( _T("")) ]; // + for trailer
		if( GetLogicalDriveStrings( lAllDriveStrings, m_pDriveStrings ) != lAllDriveStrings - 1 )
			return -2;
	_ASSERT( m_pDriveStrings != NULL );

	// this structure is used to enter items into the CComboBoxEx, preset
	// some parts before loop to fill box starts; I need to set both 
	// standard and selected images or I won't see an icon when an entry
	// is selected; the lParam is set so I can have direct access to the
	// selected root path.

	COMBOBOXEXITEM CBEItem;
	CBEItem.mask		= CBEIF_IMAGE | CBEIF_SELECTEDIMAGE | CBEIF_TEXT | CBEIF_LPARAM;
	CBEItem.cchTextMax	= 0;	// is ignored
	CBEItem.iItem		= -1; // insert at end
  
	// now loop over each drive (string)

	_TCHAR *pDriveString = m_pDriveStrings;
	size_t  lDriveString = strlen( pDriveString );
	DWORD		dIconSize    = bLargeIcons ? SHGFI_LARGEICON : SHGFI_SMALLICON;

	while( lDriveString > 0 )
	{
    // retrieve display string and icon handle

		SHFILEINFO FileInfo;
		DWORD r = SHGetFileInfo( pDriveString, 0, &FileInfo, sizeof( FileInfo ),
			SHGFI_DISPLAYNAME | SHGFI_SYSICONINDEX | dIconSize );
		if( r == 0 ) // failure - which can be ignored 
		{
			TRACE0( "SHGetFileInfo failed, no more details available\n" );
		}
		else
		{
			// insert icon and string into list box

			CBEItem.pszText = FileInfo.szDisplayName;
			CBEItem.lParam  = ( LPARAM )pDriveString;

			CBEItem.iSelectedImage	=
			CBEItem.iImage			= FileInfo.iIcon; // index into system image list

			if(GetDriveType(pDriveString)==DRIVE_FIXED || GetDriveType(pDriveString)==DRIVE_REMOVABLE)
				VERIFY( InsertItem( &CBEItem ) >= 0 );
			}

		// setup for next drive string (next round in loop)

		pDriveString += lDriveString + 1;
		lDriveString = strlen( pDriveString );
	}

	// have items in list, now provide image list: it seems I cannot just
	// pass the system image list (see notes on System Image List by Marc
	// Otway) so I create a copy on the fly (code based also on Marc's)

	_ASSERT( m_pImageList == NULL );
	m_pImageList = new CImageList;

	// load the system image list - use an arbitrary file extension for the
	// call to SHGetFileInfo (we don't want to touch the disk, so use
	// FILE_ATTRIBUTE_NORMAL && SHGFI_USEFILEATTRIBUTES)

	SHFILEINFO FileInfo;
	VERIFY( m_pImageList->Attach(( HIMAGELIST )SHGetFileInfo( _T(".txt"),
		FILE_ATTRIBUTE_NORMAL, &FileInfo, sizeof( FileInfo ),
		SHGFI_USEFILEATTRIBUTES | SHGFI_SYSICONINDEX | dIconSize )));
	
	// make the background colour transparent, works better for lists etc.

	m_pImageList->SetBkColor( CLR_NONE );

	// don't forget to set it up!

	VERIFY( SetImageList( m_pImageList ) == NULL );

	// done.

	return GetCount();
}