Exemple WriteRead
WriteRead.cpp crée un jeu de propriétés, écrit une propriété, ferme et rouvre le jeu de propriétés, puis lit la propriété. Cet exemple d’application crée le fichier « WriteRead.stg » dans le répertoire actif. Il crée des jeux de propriétés dans un fichier de stockage de structure, mais une modification d’une ligne l’amène à créer des jeux de propriétés de système de fichiers NTFS.
//+===================================================================
//
// To build:
// cl /GX WriteRead.cpp
//
//+===================================================================
#define WIN32_LEAN_AND_MEAN
#define UNICODE
#define _UNICODE
#include <stdio.h>
#include <windows.h>
#include <ole2.h>
// Implicitly link ole32.dll
#pragma comment( lib, "ole32.lib" )
// From uuidgen.exe:
const FMTID fmtid = { /* d170df2e-1117-11d2-aa01-00805ffe11b8 */
0xd170df2e,
0x1117,
0x11d2,
{0xaa, 0x01, 0x00, 0x80, 0x5f, 0xfe, 0x11, 0xb8}
};
EXTERN_C void wmain()
{
HRESULT hr = S_OK;
IPropertySetStorage *pPropSetStg = NULL;
IPropertyStorage *pPropStg = NULL;
WCHAR *pwszError = L"";
PROPSPEC propspec;
PROPVARIANT propvarWrite;
PROPVARIANT propvarRead;
try
{
// Create a file and a property set within it.
hr = StgCreateStorageEx( L"WriteRead.stg",
STGM_CREATE|STGM_SHARE_EXCLUSIVE|STGM_READWRITE,
STGFMT_STORAGE,
// STGFMT_STORAGE => Structured Storage
// property sets
// STGFMT_FILE => NTFS file system
// property sets
0, NULL, NULL,
IID_IPropertySetStorage,
reinterpret_cast<void**>(&pPropSetStg) );
if( FAILED(hr) ) throw L"Failed StgCreateStorageEx";
hr = pPropSetStg->Create( fmtid, NULL, PROPSETFLAG_DEFAULT,
STGM_CREATE|STGM_READWRITE|STGM_SHARE_EXCLUSIVE,
&pPropStg );
if( FAILED(hr) ) throw L"Failed IPropertySetStorage::Create";
// Write a Unicode string property to the property set
propspec.ulKind = PRSPEC_LPWSTR;
propspec.lpwstr = L"Property Name";
propvarWrite.vt = VT_LPWSTR;
propvarWrite.pwszVal = L"Property Value";
hr = pPropStg->WriteMultiple( 1, &propspec, &propvarWrite,
PID_FIRST_USABLE );
if( FAILED(hr) )
throw L"Failed IPropertyStorage::WriteMultiple";
// Not required, but give the property set a friendly
// name.
PROPID propidDictionary = PID_DICTIONARY;
WCHAR *pwszFriendlyName =
L"Write/Read Properties Sample Property Set";
hr = pPropStg->WritePropertyNames( 1, &propidDictionary,
&pwszFriendlyName );
if( FAILED(hr) )
throw L"Failed IPropertyStorage::WritePropertyNames";
// Commit changes to the property set.
hr = pPropStg->Commit(STGC_DEFAULT);
if( FAILED(hr) )
throw L"Failed IPropertyStorage::Commit";
// Close and reopen everything.
// By using the STGFMT_ANY flag in the StgOpenStorageEx call,
// it does not matter if this is a Structured Storage
// property set or an NTFS file system property set
// (for more information see the StgCreateStorageEx
// call above).
pPropStg->Release(); pPropStg = NULL;
pPropSetStg->Release(); pPropSetStg = NULL;
hr = StgOpenStorageEx( L"WriteRead.stg",
STGM_READ|STGM_SHARE_DENY_WRITE,
STGFMT_ANY,
0, NULL, NULL,
IID_IPropertySetStorage,
reinterpret_cast<void**>(&pPropSetStg) );
if( FAILED(hr) )
throw L"Failed StgOpenStorageEx";
hr = pPropSetStg->Open( fmtid, STGM_READ|STGM_SHARE_EXCLUSIVE,
&pPropStg );
if( FAILED(hr) )
throw L"Failed IPropertySetStorage::Open";
// Read the property back and validate it
hr = pPropStg->ReadMultiple( 1, &propspec, &propvarRead );
if( FAILED(hr) )
throw L"Failed IPropertyStorage::ReadMultiple";
if( S_FALSE == hr )
throw L"Property didn't exist after reopening the
property set";
else if( propvarWrite.vt != propvarRead.vt )
throw L"Property types didn't match after reopening the
property set";
else if( 0 != wcscmp( propvarWrite.pwszVal,
propvarRead.pwszVal ))
throw L"Property values didn't match after reopening the
property set";
else
wprintf( L"Success\n" );
}
catch( const WCHAR *pwszError )
{
wprintf( L"Error: %s (hr=%08x)\n", pwszError, hr );
}
PropVariantClear( &propvarRead );
if( pPropStg ) pPropStg->Release();
if( pPropSetStg ) pPropSetStg->Release();
}
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