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: }

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In order to get the printers info installed on your local computer or on the network, you just need to query the “Win32_Printers” Windows Management Instrumentation (WMI) class by using the classes provided in the System.Management namespace. The process is fairly simple. First of all create an instance of ManagementObjectSearcher class and pass your query to the constructor of this class. The Get() method of the ManagementObjectSearcher class will return the an instance of ManagementObjectCollection class. Each ManagementObject instance in ManagementObjectCollection contains information about a single printer. Following is the code snippet to achieve this.

   1: protected void Page_Load(object sender, EventArgs e)

   2: {

   3:      ManagementObjectSearcher searcher;

   4:     string Win32_Printer = "SELECT * FROM Win32_Printer";

   5:     searcher = new ManagementObjectSearcher(Win32_Printer);

   6:  

   7:     foreach (ManagementObject mgmtObj in searcher.Get())

   8:     {

   9:         string Description = "Printer Name: " + mgmtObj["Name"].ToString()

  10:             + " System Name : " + mgmtObj["SystemName"].ToString()

  11:             + " Print Processor : " + mgmtObj["PrintProcessor"].ToString();

  12:         Response.Write("Description = " + Description);

  13:         Response.Write("Device ID = " +  mgmtObj["DeviceID"].ToString());

  14:     }

  15: }

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Recently i had a requirement at work to create an ASP.NET web page which can only be viewed by registered clients. Clients were registered using their network adapter’s MAC address. The solution was pretty simple and straight forward. One just needs to reference the System.Management namespace and query using the “Win32_NetworkAdapterConfiguration” Windows Management Instrumentation (WMI) Class. Following is the code snippet listing on how to achieve this.

   1: protected void Page_Load(object sender, EventArgs e)

   2: {

   3:     ManagementObjectSearcher searcher;

   4:     string ip = string.Empty;

   5:     string Win32_NetworkAdapterConfiguration = "Select * FROM  "

   6:     + "Win32_NetworkAdapterConfiguration WHERE IPEnabled = 'TRUE'";

   7:     searcher = new ManagementObjectSearcher(Win32_NetworkAdapterConfiguration);

   8:  

   9:     foreach (ManagementObject mgmtObj in searcher.Get())

  10:     {

  11:         Response.Write("Host IP Address = " + ((string[])mgmtObj["IPAddress"])[0]);

  12:         Response.Write("<br />");

  13:         Response.Write("Host MAC Address = " + mgmtObj["MACAddress"].ToString());

  14:     }

  15: }

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To implement a custom Role Provider, you will need to provide a concrete implementation of the RoleProvider class to ASP.NET, and plug it into the system through appropriate configuration settings.

The first step in implementing the custom provider is to derive a class from the RoleProvider abstract base class. To provide a complete implementation, you will need to provide overrides for all of the methods and properties of the RoleProvider class.

In this case I am going to create my own custom role provider class named MyRoleProvider.cs that derives from the RoleProvider class as shown in the following figure.

The RoleProvider class resides in the System.Web.Security namespace and ProviderBase class from which RoleProvider class inherits, resides in namespace System.Configuration.Providers. Make sure you reference both of the namespaces in your project.

When you inherit from RoleProvider you have to implement all the methods and properties defined in that class because it’s an abstract class. In my case I’m going to implement only one method named GetRolesForUser() which takes a string parameter “username” and returns the Roles against that user. All the other methods through not implemented exception and hence are not shown. Here is the code

   1: public override string[] GetRolesForUser(string username) {

   2:  

   3:             string[] roleArray = null;

   4:  

   5:             RoleService roleService = new RoleService();

   6:  

   7:             Role[] roles = roleService.GetRolesForUser(username);

   8:  

   9:             roleArray = new string[roles.Length];

  10:  

  11:             for (int i = 0; i < roles.Length; i++) {

  12:                 roleArray[i] = roles[i].Name;

  13:             }

  14:             return roleArray;

  15:         }

Now, to use the newly created MyRoleProvider I have to enable and configure the RoleManager in the web.config. Here is how

   1: <roleManager enabled="true" defaultProvider="MyRoleProvider">

   2:    <providers>

   3:       <clear/>

   4:       <add name="MyRoleProvider" type="Afeef.Configuration.Providers.MyRoleProvider"/>

   5:    </providers>

   6: </roleManager>

I next need to add security to my application through authorization section in the web.config file.

   1: <authorization>        

   2:    <deny roles="Guest"/>

   3:    <allow roles="Administrator"/>

   4: </authorization>

Now only users with role of Administrator can view the pages in this application. Whenever a user tries to visit one of the pages in the application, the GetRolesForUser() method is called in our MyRoleProvider class to determine whether the user is in Administrator Role. If he is, the page is served. If not, a security exception is thrown, not allowing the page to be viewed.

This is it, you’re done!

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