Connecting to WMI Remotely with C#
As with other languages such as PowerShell, VBScript, or C++, you can use C# to remotely monitor the hardware and software on remote computers. Remote connections for managed code are accomplished through the Microsoft.Management.Infrastructure namespace. (Previous versions of WMI used the System.Management namespace, which is included here for completeness.)
Note
System.Management was the original .NET namespace used to access WMI; however, the APIs in this namespace generally are slower and do not scale as well relative to their more modern Microsoft.Management.Infrastructure counterparts.
Connecting remotely using classes in the Microsoft.Management.Infrastructure namespace uses DCOM as the underlying remote mechanism. WMI remote connections must comply with DCOM security requirements for impersonation and authentication. By default, a scope is bound to the local computer and the "Root\CIMv2" system namespace. However, you can change both the computer, domain, and WMI namespace that you access. You can also set authority, impersonation, credentials, and other connection options.
To connect to WMI remotely with C# (Microsoft.Management.Infrastructure)
Create a session on the remote machine with a call to CimSession.Create.
If you are connecting to a remote computer using the same credentials (domain and user name) you are logged on with, then you can specify the name of the computer in the Create call. Once you have the returned CimSession object, you can then make your WMI query.
using Microsoft.Management.Infrastructure; ... string Namespace = @"root\cimv2"; string OSQuery = "SELECT * FROM Win32_OperatingSystem"; CimSession mySession = CimSession.Create("Computer_B"); IEnumerable<CimInstance> queryInstance = mySession.QueryInstances(Namespace, "WQL", OSQuery);For more information on making WMI queries with the Microsoft.Management.Infrastructure API in C#, see Retrieving WMI Class or Instance Data.
If you wish to set different options for your connection, such as different credentials, locale or Impersonation levels, you need to use a CimSessionOptions object in your call to CimSession.Create.
CimSessionOptions is a base class for WSManSessionOptions and DComSessionOptions. You can use either to set the options on your WS-Man and DCOM sessions, respectively. The following code sample describes using a DComSessionOptions object to set the Impersonation level to Impersonate.
string computer = "Computer_B" DComSessionOptions DComOptions = new DComSessionOptions(); DComOptions.Impersonation = ImpersonationType.Impersonate; CimSession Session = CimSession.Create(computer, DComOptions);If you wish to set the credentials for your connection, you will need to create and add a CimCredentials object to your CimSessionOptions.
The following code sample describes creating a WSManSessionOptions class, filling it with the proper CimSessionOptions, and using it in a CimSession.Create call.
string computer = “Computer_B”; string domain = “Domain1″; string username = “User1″; string plaintextpassword; //Retrieve password from the user. //For the complete code, see the sample at the bottom of this topic. CimCredential Credentials = new CimCredential(PasswordAuthenticationMechanism.Default, domain, username, securepassword); WSManSessionOptions SessionOptions = new WSManSessionOptions(); SessionOptions.AddDestinationCredentials(Credentials); CimSession Session = CimSession.Create(computer, SessionOptions);It is generally recommended that you do not hardcode a password into your applications; as the above code sample indicates, whenever possible try to query your user for the password, and store it securely.
WMI is intended to monitor the hardware and software on remote computers. Remote connections for WMI v1 is accomplished through the ManagementScope object.
To connect to WMI remotely with C# (System.Management)
Create a ManagementScope object, using the name of the computer and the WMI path, and connect to your target with a call to ManagementScope.Connect().
If you are connecting to a remote computer using the same credentials (domain and user name) you are logged on with, then you only have to specify the WMI path. Once you have connected, you can make your WMI query.
using System.Management; ... ManagementScope scope = new ManagementScope("\\\\Computer_B\\root\\cimv2"); scope.Connect(); ObjectQuery query = new ObjectQuery("SELECT * FROM Win32_OperatingSystem"); ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope, query);For more information on making WMI queries with the System.Management API in C#, see Retrieving WMI Class or Instance Data.
If you connect to a remote computer in a different domain or using a different user name and password, then you must use a ConnectionOptions object in the call to the ManagementScope.
The ConnectionOptions contains properties for describing the Authentication, Impersonation, username, password, and other connection options. The following code sample describes using a ConnectionOptions to set the Impersonation Level to Impersonate.
ConnectionOptions options = new ConnectionOptions(); options.Impersonation = System.Management.ImpersonationLevel.Impersonate; ManagementScope scope = new ManagementScope("\\\\FullComputerName\\root\\cimv2", options); scope.Connect(); ObjectQuery query = new ObjectQuery("SELECT * FROM Win32_OperatingSystem"); ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope,query);Generally speaking, it is recommended that you set your Impersonation level to Impersonate unless explicitly needed otherwise. Further, try to avoid writing your name and password into C# code. (If possible, see if you can query the user to dynamically supply them at runtime.)
For more examples of setting different properties on a remote WMI connection, see the Examples section of the ConnectionOptions reference page.
Microsoft.Management.Infrastructure Example
The following C# code example, based on the following blog post on TechNet, describes how to use CimCredentials and WSManSessionOptions to set credentials on a remote connection.
using System;
using System.Text;
using System.Threading;
using Microsoft.Management.Infrastructure;
using Microsoft.Management.Infrastructure.Options;
using System.Security;
namespace SMAPIQuery
{
class Program
{
static void Main(string[] args)
{
string computer = "Computer_B";
string domain = "DOMAIN";
string username = "AdminUserName";
string plaintextpassword;
Console.WriteLine("Enter password:");
plaintextpassword = Console.ReadLine();
SecureString securepassword = new SecureString();
foreach (char c in plaintextpassword)
{
securepassword.AppendChar(c);
}
// create Credentials
CimCredential Credentials = new CimCredential(PasswordAuthenticationMechanism.Default,
domain,
username,
securepassword);
// create SessionOptions using Credentials
WSManSessionOptions SessionOptions = new WSManSessionOptions();
SessionOptions.AddDestinationCredentials(Credentials);
// create Session using computer, SessionOptions
CimSession Session = CimSession.Create(computer, SessionOptions);
var allVolumes = Session.QueryInstances(@"root\cimv2", "WQL", "SELECT * FROM Win32_Volume");
var allPDisks = Session.QueryInstances(@"root\cimv2", "WQL", "SELECT * FROM Win32_DiskDrive");
// Loop through all volumes
foreach (CimInstance oneVolume in allVolumes)
{
// Show volume information
if (oneVolume.CimInstanceProperties["DriveLetter"].ToString()[0] > ' ' )
{
Console.WriteLine("Volume ‘{0}’ has {1} bytes total, {2} bytes available",
oneVolume.CimInstanceProperties["DriveLetter"],
oneVolume.CimInstanceProperties["Size"],
oneVolume.CimInstanceProperties["SizeRemaining"]);
}
}
// Loop through all physical disks
foreach (CimInstance onePDisk in allPDisks)
{
// Show physical disk information
Console.WriteLine("Disk {0} is model {1}, serial number {2}",
onePDisk.CimInstanceProperties["DeviceId"],
onePDisk.CimInstanceProperties["Model"].ToString().TrimEnd(),
onePDisk.CimInstanceProperties["SerialNumber"]);
}
Console.ReadLine();
}
}
}
System.Management Example
The following C# code sample describes a general remote connection, using the System.Management objects.
using System;
using System.Management;
public class RemoteConnect
{
public static void Main()
{
ConnectionOptions options = new ConnectionOptions();
options.Impersonation = System.Management.ImpersonationLevel.Impersonate;
ManagementScope scope = new ManagementScope("\\\\FullComputerName\\root\\cimv2", options);
scope.Connect();
//Query system for Operating System information
ObjectQuery query = new ObjectQuery("SELECT * FROM Win32_OperatingSystem");
ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope,query);
ManagementObjectCollection queryCollection = searcher.Get();
foreach ( ManagementObject m in queryCollection)
{
// Display the remote computer information
Console.WriteLine("Computer Name : {0}", m["csname"]);
Console.WriteLine("Windows Directory : {0}", m["WindowsDirectory"]);
Console.WriteLine("Operating System : {0}", m["Caption"]);
Console.WriteLine("Version : {0}", m["Version"]);
Console.WriteLine("Manufacturer : {0}", m["Manufacturer"]);
}
}
}
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