两种办法实现安全删除(断开)U盘的DELPHI源码

function OpenVolume(ADrive: char): THandle; var RootName, VolumeName: string; AccessFlags: DWORD; begin //RootName := ADrive + ':' + #134; // ADrive + ':\' kills the syntax highlighting RootName := ADrive + ':' + #92; case GetDriveType(PChar(RootName)) of DRIVE_REMOVABLE: AccessFlags := GENERIC_READ or GENERIC_WRITE; DRIVE_CDROM: AccessFlags := GENERIC_READ; else Result := INVALID_HANDLE_VALUE; exit; end; VolumeName := Format('\\.\%s:', [ADrive]); Result := CreateFile(PChar(VolumeName), AccessFlags, FILE_SHARE_READ or FILE_SHARE_WRITE, nil, OPEN_EXISTING, 0, 0); if Result = INVALID_HANDLE_VALUE then RaiseLastWin32Error; end; function LockVolume(AVolumeHandle: THandle): boolean; const LOCK_TIMEOUT = 10 * 1000; // 10 Seconds LOCK_RETRIES = 20; LOCK_SLEEP = LOCK_TIMEOUT div LOCK_RETRIES; // #define FSCTL_LOCK_VOLUME CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 6, METHOD_BUFFERED, FILE_ANY_ACCESS) FSCTL_LOCK_VOLUME = (9 shl 16) or (0 shl 14) or (6 shl 2) or 0; var Retries: integer; BytesReturned: Cardinal; begin for Retries := 1 to LOCK_RETRIES do begin Result := DeviceIoControl(AVolumeHandle, FSCTL_LOCK_VOLUME, nil, 0, nil, 0, BytesReturned, nil); if Result then break; Sleep(LOCK_SLEEP); end; end; function DismountVolume(AVolumeHandle: THandle): boolean; const // #define FSCTL_DISMOUNT_VOLUME CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 8, METHOD_BUFFERED, FILE_ANY_ACCESS) FSCTL_DISMOUNT_VOLUME = (9 shl 16) or (0 shl 14) or (8 shl 2) or 0; var BytesReturned: Cardinal; begin Result := DeviceIoControl(AVolumeHandle, FSCTL_DISMOUNT_VOLUME, nil, 0, nil, 0, BytesReturned, nil); if not Result then RaiseLastWin32Error; end; function PreventRemovalOfVolume(AVolumeHandle: THandle; APreventRemoval: boolean): boolean; const // #define IOCTL_STORAGE_MEDIA_REMOVAL CTL_CODE(IOCTL_STORAGE_BASE, 0x0201, METHOD_BUFFERED, FILE_READ_ACCESS) IOCTL_STORAGE_MEDIA_REMOVAL = ($2d shl 16) or (1 shl 14) or ($201 shl 2) or 0; type TPreventMediaRemoval = record PreventMediaRemoval: BOOL; end; var BytesReturned: Cardinal; PMRBuffer: TPreventMediaRemoval; begin PMRBuffer.PreventMediaRemoval := APreventRemoval; Result := DeviceIoControl(AVolumeHandle, IOCTL_STORAGE_MEDIA_REMOVAL, @PMRBuffer, SizeOf(TPreventMediaRemoval), nil, 0, BytesReturned, nil); if not Result then RaiseLastWin32Error; end; function AutoEjectVolume(AVolumeHandle: THandle): boolean; const // #define IOCTL_STORAGE_EJECT_MEDIA CTL_CODE(IOCTL_STORAGE_BASE, 0x0202, METHOD_BUFFERED, FILE_READ_ACCESS) IOCTL_STORAGE_EJECT_MEDIA = ($2d shl 16) or (1 shl 14) or ($202 shl 2) or 0; var BytesReturned: Cardinal; begin Result := DeviceIoControl(AVolumeHandle, IOCTL_STORAGE_EJECT_MEDIA, nil, 0, nil, 0, BytesReturned, nil); if not Result then RaiseLastWin32Error; end; function EjectVolume(ADrive: char): boolean; var VolumeHandle: THandle; begin Result := FALSE; // Open the volume VolumeHandle := OpenVolume(ADrive); //ShowMessage(IntToStr(VolumeHandle)+sLineBreak+IntToStr(INVALID_HANDLE_VALUE)); if VolumeHandle = INVALID_HANDLE_VALUE then exit; try // Lock and dismount the volume if LockVolume(VolumeHandle) and DismountVolume(VolumeHandle) then begin // Set prevent removal to false and eject the volume if PreventRemovalOfVolume(VolumeHandle, FALSE) then AutoEjectVolume(VolumeHandle); end; finally // Close the volume so other processes can use the drive CloseHandle(VolumeHandle); end; end; //使用方法： { Drive:='C:\'; EjectVolume(Drive[1]); }