Getting the USB Devices Information using WMI

Afeef さんのプロフィールAfeef Ahmed Janjuaフォトブログリストその他

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5月9日

Getting the USB Devices Information using WMI

One day at work i had a unique requirement. I wanted to list the usb devices attached with the client and then get their vendor or product id to store at the backend. I started search on google and found out that their was next to nothing on this subject. I also found out that many people were interested in the solution. Somehow after reading a awful amount of msdn documentation, it came to my understanding that i have to query two different Windows Management Instrumentation (WMI) classes to achieve the goal.

First of all i had to Enable Privilages on the ManagementScope object just to make sure that every thing works fine. Next came the QueryObject class that i used to create my first query using the “Win32_USBControllerDevice” WMI class. Using these ManagementScope and QueryObject instances i created an instance of ManagementObjectSearcher class and called its Get() method. This Get() method returned me an instance of ManagementObjectCollection class. I was interested in the Dependent property in each of the ManagementObject in this ManagementObjectCollection instance.

The Dependent property in each ManagementObject instance contains the DeviceId of a single usb device. So i extracted the DeviceId and created a second query based on this DeviceId. This time i queried “Win32_PnPEntity” WMI class. Which is a class for plug-n-play entities attached to the system. As you may guess there are all sorts of plug-n-play devices attached with the system. That’s precisely why we need the DeviceId in the query string. I again queried the hardware using the classes discussed above and got yet another a ManagementObjectCollection instance. For each ManagementObject instance i accessed my desired properties. I was mainly interested in the following properties

Device Description
Manufacturer (if any)
Device VendorId or ProductId
DeviceId (if any)

Following is a complete listing of the code

   1: protected void Page_Load(object sender, EventArgs e)   2: {   3:      ManagementScope scope = new ManagementScope("root\\CIMV2");   4:     scope.Options.EnablePrivileges = true;   5:     string Win32_USBControlerDevice = "Select * From Win32_USBControllerDevice";   6:     ObjectQuery query = new ObjectQuery(Win32_USBControlerDevice);   7:     ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope, query);   8:     foreach (ManagementObject mgmtObj in searcher.Get())   9:     {  10:         string strDeviceName = mgmtObj["Dependent"].ToString();  11:         string strQuotes = "'";  12:         strDeviceName = strDeviceName.Replace("\"", strQuotes);  13:         string[] arrDeviceName = strDeviceName.Split('=');  14:         strDeviceName = arrDeviceName[1];  15:         string Win32_PnPEntity = "Select * From Win32_PnPEntity "  16:             + "Where DeviceID =" + strDeviceName;  17:         ManagementObjectSearcher mySearcher =   18:             new ManagementObjectSearcher(Win32_PnPEntity);  19:         foreach (ManagementObject mobj in mySearcher.Get())  20:         {  21:             string strDeviceID = mobj["DeviceID"].ToString();  22:             string[] arrDeviceID = strDeviceID.Split('\\');  23:             Response.Write("<br />");  24:             Response.Write("<br />");  25:             Response.Write("Device Description = "   26:                     + mobj["Description"].ToString());  27:             Response.Write("<br />");  28:             if (mobj["Manufacturer"] != null)  29:             {  30:                 Response.Write("Device Manufacturer = "   31:                     + mobj["Manufacturer"].ToString());  32:                 Response.Write("<br />");  33:             }  34:             Response.Write("Device Version ID & Vendor ID = " + arrDeviceID[1]);  35:             Response.Write("<br />");  36:             Response.Write("Device ID = " + arrDeviceID[2].Trim('{', '}'));  37:             Response.Write("<br />");  38:         }  39:     }  40: }