WMI(WindowsManagement Instrumentation ) 非常强大，它可以以数据库的形式查询你的电脑的软件和硬件，在它的数据库里面，时刻保存着最新的软件信息和硬件信息，因此你可以用WMI来检测CUP 主频、温度，读取WINDOWS的进程.........
本文就介绍如何使用WMI读取USB设备的PID和VID码
1. Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
2.
3. Dialogs, StdCtrls, ExtCtrls,ActiveX, ComObj;
4.
5.
6.
7. procedure TForm1.Button2Click(Sender: TObject);
8.
9. var
10.
11. Locator: OleVariant;
12.
13. WMI: OleVariant;
14.
15. RET: OleVariant;
16.
17. Enum: IEnumVariant;
18.
19. Tmp: OleVariant;
20.
21. Value: Cardinal;
22.
23. begin;
24.
25. Locator := CreateOleObject('WbemScripting.SWbemLocator');
26.
27. WMI := Locator.ConnectServer('.', '', '', '');
28.
29. Ret := WMI.ExecQuery('SELECT * FROM Win32_USBHub');//这里Win32_USBHub为检测项，详见下表
30.
31.
32.
33. Enum:= IUnknown(RET._NewEnum) as IEnumVariant;
34.
35. while (Enum.Next(1, Tmp, Value) = S_OK) do
36.
37. begin
38.
39. if Tmp.Name='USB Mass Storage Device' then
40.
41. ShowMessage('这个u盘的硬件特征码是'+Tmp.PNPDeviceID);//Tmp为检测到返回的数据集合，其中PNPDeviceID为集合中的对象，包含了PID和VID码
42.
43. end;
44.
45.
46.
47. end;
48.
49.
50.
51. Win32_USBHub只是冰山一角，常用的还有以下
52.
53.
54.
55. "Win32_1394Controller" ,
56.
57. "Win32_BaseBoard" ,
58.
59. "Win32_Battery" ,
60.
61. "Win32_BIOS" ,
62.
63. "Win32_Bus" ,
64.
65. "Win32_CacheMemory" ,
66.
67. "Win32_CDROMDrive" ,
68.
69. "Win32_CurrentProbe" ,
70.
71. "Win32_DesktopMonitor" ,
72.
73. "Win32_DeviceMemoryAddress" ,
74.
75. "Win32_DiskDrive" ,
76.
77. "Win32_DisplayConfiguration" ,
78.
79. "Win32_DisplayControllerConfiguration",
80.
81. "Win32_DMAChannel" ,
82.
83. "Win32_Fan" ,
84.
85. "Win32_FloppyController" ,
86.
87. "Win32_FloppyDrive" ,
88.
89. "Win32_HeatPipe" ,
90.
91. "Win32_IDEController" ,
92.
93. "Win32_InfraredDevice" ,
94.
95. "Win32_IRQResource" ,
96.
97. "Win32_Keyboard" ,
98.
99. "Win32_MemoryArray" ,
100.
101. "Win32_MemoryDevice" ,
102.
103. "Win32_MotherboardDevice" ,
104.
105. "Win32_NetworkAdapter" ,
106.
107. "Win32_NetworkAdapterConfiguration" ,
108.
109. "Win32_OnBoardDevice" ,
110.
111. "Win32_ParallelPort" ,
112.
113. "Win32_PCMCIAController" ,
114.
115. "Win32_PhysicalMemory" ,
116.
117. "Win32_PhysicalMemoryArray" ,
118.
119. "Win32_PnPEntity" ,
120.
121. "Win32_PointingDevice" ,
122.
123. "Win32_PortableBattery" ,
124.
125. "Win32_PortConnector" ,
126.
127. "Win32_PortResource" ,
128.
129. "Win32_POTSModem" ,
130.
131. "Win32_PowerManagementEvent" ,
132.
133. "Win32_Printer" ,
134.
135. "Win32_PrinterConfiguration" ,
136.
137. "Win32_PrintJob" ,
138.
139. "Win32_Processor" ,
140.
141. "Win32_Refrigeration" ,
142.
143. "Win32_SerialPort" ,
144.
145. "Win32_SerialPortConfiguration" ,
146.
147. "Win32_SMBIOSMemory" ,
148.
149. "Win32_SoundDevice" ,
150.
151. "Win32_SystemEnclosure" ,
152.
153. "Win32_SystemMemoryResource" ,
154.
155. "Win32_SystemSlot" ,
156.
157. "Win32_TapeDrive" ,
158.
159. "Win32_TemperatureProbe" ,
160.
161. "Win32_UninterruptiblePowerSupply" ,
162.
163. "Win32_USBController" ,
164.
165. "Win32_VideoConfiguration" ,
166.
167. "Win32_VideoController" ,
168.
169. "Win32_VoltageProbe" ,