用SetupDiGetClassDevs枚舉裝置

網
絡上有段代碼是用SetupDiGetClassDevs枚舉隨身碟對應的盤符。代碼中判斷裝置是否是u盤的辦法是首先用
GUID_DEVINTERFACE_VOLUME調用SetupDiGetClassDevs後再
SetupDiEnumDeviceInterfaces，SetupDiGetDeviceInterfaceDetail……最後還需要和事先傳進來
的Device ID比較。

實際上，經過實驗，我找到另外一個簡單一點的辦法：

首先是用
SetupDiGetClassDevs枚舉GUID_DEVINTERFACE_USB_DEVICE，找到所有USB裝置。然後用
SetupDiGetClassDevs枚舉GUID_DEVINTERFACE_VOLUME，找到所有VOLUME後依次遞迴取其Parent，直到
到達HTREE/ROOT/0或者某個Parent等於前面得到的USB裝置為止。

值得注意的是，GUID_DEVINTERFACE_USB_DEVICE、GUID_DEVINTERFACE_DISK枚舉出的裝置只有一個Child，就是自身。

下面是SetupDiGetClassDevs在我機器上的一些結果：

Volume

{4D36E965-E325-11CE-BFC1-08002BE10318}
IDE/CDROMHL-DT-ST_CD-ROM_GCR-8523B_______________1.02____/5&4DE3C4&0&0.0.0
{4D36E965-E325-11CE-BFC1-08002BE10318}
SCSI/CDROM&VEN_GENERIC&PROD_DVD-ROM&REV_1.0/2&12B1DE20&0&000
{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/REMOVABLEMEDIA/7&35EAC781&0&RM
{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/VOLUME/1&30A96598&0&SIGNATURE8150814OFFSET27FCC3000LENGTH27FCB3400
{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/VOLUME/1&30A96598&0&SIGNATURE8150814OFFSET4FF97E200LENGTH4510E1E00
{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/VOLUME/1&30A96598&0&SIGNATURE8150814OFFSET7E00LENGTH27FCB3400

Disk

{4D36E967-E325-11CE-BFC1-08002BE10318}
IDE/DISKST340015A_______________________________3.15____/4C35484158483150202020202020202020202020
{4D36E967-E325-11CE-BFC1-08002BE10318}
USBSTOR/DISK&VEN_GENERIC&PROD_USB_FLASH_DRIVE&REV_1.00/6&2ECD5725&1

USB

{36FC9E60-C465-11CF-8056-444553540000}
USB/VID_1043&PID_8012/5&1E5B5D9&0&5

PARTITION

{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/REMOVABLEMEDIA/7&35EAC781&0&RM

下面是一些VOLUME的父系層次：

{4D36E965-E325-11CE-BFC1-08002BE10318}
IDE/CDROMHL-DT-ST_CD-ROM_GCR-8523B_______________1.02____/5&4DE3C4&0&0.0.0
PCIIDE/IDECHANNEL/4&14E96D70&0&1
PCI/VEN_8086&DEV_24DB&SUBSYS_300E103C&REV_02/3&13C0B0C5&0&F9
ACPI/PNP0A03/1
ACPI_HAL/PNP0C08/0
ROOT/ACPI_HAL/0000
HTREE/ROOT/0

{4D36E965-E325-11CE-BFC1-08002BE10318}
SCSI/CDROM&VEN_GENERIC&PROD_DVD-ROM&REV_1.0/2&12B1DE20&0&000
PCI/D347PRT/0000
ROOT/SYSTEM/0003
HTREE/ROOT/0

{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/REMOVABLEMEDIA/7&35EAC781&0&RM
USBSTOR/DISK&VEN_GENERIC&PROD_USB_FLASH_DRIVE&REV_1.00/6&2ECD5725&1
USB/VID_1043&PID_8012/5&1E5B5D9&0&5
USB/ROOT_HUB20/4&386BDE3F&0
PCI/VEN_8086&DEV_24DD&SUBSYS_300E103C&REV_02/3&13C0B0C5&0&EF
ACPI/PNP0A03/1
ACPI_HAL/PNP0C08/0
ROOT/ACPI_HAL/0000
HTREE/ROOT/0

{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/VOLUME/1&30A96598&0&SIGNATURE8150814OFFSET27FCC3000LENGTH27FCB3400
ROOT/FTDISK/0000
HTREE/ROOT/0

{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/VOLUME/1&30A96598&0&SIGNATURE8150814OFFSET4FF97E200LENGTH4510E1E00
ROOT/FTDISK/0000
HTREE/ROOT/0

{71A27CDD-812A-11D0-BEC7-08002BE2092F}
STORAGE/VOLUME/1&30A96598&0&SIGNATURE8150814OFFSET7E00LENGTH27FCB3400
ROOT/FTDISK/0000
HTREE/ROOT/0

對照一下可以發現以下值得注意的地方：

1、IDE硬碟中VOLUME的裝置ID包括了VOLUME的位置、長度
2、IDE硬碟中VOLUME的Parents中不包括該硬碟的Device ID
3、隨身碟中VOLUME的Parents中包括該隨身碟的Device ID
4、隨身碟中VOLUME的Device ID裡有“REMOVABLEMEDIA”標記