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 »  Home  »  .NET Framework  »  WMI connections made easy in VB.NET  »  Walking Through The Sample
WMI connections made easy in VB.NET
by Martin de Klerk | Published  04/24/2005 | .NET Framework | Rating:
Walking Through The Sample

The next part shows the sample code that is included in the ConnectionTester source. Just remove the module 'Sample' to incorporate the ConnectionTester class in your own project. As it is heavily commented, I won't insult the readers intelligence by explaining what's being explained:

   Dim WmiConn As New ConnectionTester
      '* point the ConnectionTester to the target computer.
      '* That can be done either by supplying the NetBios-name or
      '* Domain-name of the (remote) computer:
      WmiConn.ServerName = "localhost"
      '* OR by supplying the IP address of the (remote) computer
      '* computer as a string like:
      '*    WmiConn.IPAddress = "127.0.0.1"
      '* OR by providing the HTTP address of the (remote) computer:
      '*    WmiConn.ServerName = "www.vbcity.com"
      '* The ConnectionTester's WMI capabilities are enabled per default.
      '* To disable them and only perform a quick online check, set the
      '* next value to False
      WmiConn.WmiCheck = True
      '* Test the connection
      Console.WriteLine("Connecting to {0}", wmiConn.ServerName)
      WmiConn.Poll()
      '* Check if target is online
      If wmiConn.IsOnLine = False Then
         Console.WriteLine("{0} is off-line.", WmiConn.ServerName)
         Exit Sub
      Else
         '* Display on-line state
         Console.WriteLine("{0} is online with IP address: {1}.", _
           WmiConn.ServerName, WmiConn.IPAddress)
      End If
      '* Check if errors occured while connecting
      If WmiConn.HasErrors = True Then
         Console.WriteLine("Error while connecting to {0}: {1}", _
           WmiConn.ServerName, WmiConn.ErrorMessage)
         Exit Sub
      End If
      '* Check if WMI connection to remote is active
      If WmiConn.WmiEnabled = False Then
         Console.WriteLine("Could not connect WMI with \{0}{1} ", _
           WmiConn.ServerName, WmiConn.WmiNamespace)
      Else
         '* Display the connection to WMI namespace
         Console.WriteLine("WMI connection with {0} established: {1}", _
           WmiConn.ServerName, WmiConn.wmiNameSpace)
         '* show operating system version running the (remote) WMI server
         Console.WriteLine("O.S. : {0} ", wmiconn.OperatingSystem)
         '* get all MSI installed programs (can take a while)
         Console.WriteLine("Retrieving information. Please wait......")
         '* Create storage for the query results
         Dim moc As System.Management.ManagementObjectCollection
         '* Instruct the (remote) WMI server to execute query
         moc = WmiConn.ExecWmiQuery("Select * From Win32_Product")
         '* when found, display program-names
         If Not moc Is Nothing Then
            Console.WriteLine(" - Programs installed on {0} -", _
              wmiConn.ServerName)
            Dim mo As System.Management.ManagementObject
            For Each mo In moc
               Console.WriteLine( mo.GetPropertyValue("Caption"))
            Next
            Console.WriteLine(" - End of list -")
         End If
      End If
You can download the demonstration copy of the Connection Tester solution from the next page.
Comments    Submit Comment

Comment #1  (Posted by an unknown user on 07/13/2005)
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This article is great. Easy to read and understand. It gave me everything I needed.
 
Comment #2  (Posted by an unknown user on 07/22/2005)
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This is a good starter. Luckily, you provide the links to the downloads at the end of the article. It's perhaps a good idea to provide them inside the text as well.
 
Comment #3  (Posted by an unknown user on 07/29/2005)
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It is perfect
 
Comment #4  (Posted by an unknown user on 08/02/2005)
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After days of crawling the net, this is the most professional article found yet on WMI & remote connectivity.

WELL DONE !
 
Comment #5  (Posted by an unknown user on 08/02/2005)
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After days of crawling the net, this is the most professional article found yet on WMI & remote connectivity.

WELL DONE !
 
Comment #6  (Posted by an unknown user on 08/24/2005)
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Great approach to introducing people to WMI. Simple to read and understand. Great Job.
 
Comment #7  (Posted by an unknown user on 09/01/2005)
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Found exactly what I needed to fix my code. Thanks
 
Comment #8  (Posted by an unknown user on 10/06/2005)
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This is a great job. In my case help me to resolve a problem with network server monitoring. Thanx for all.
 
Comment #9  (Posted by an unknown user on 10/17/2005)
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Nice and simple.
 
Comment #10  (Posted by an unknown user on 11/12/2005)
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Impeccably presented.
 
Comment #11  (Posted by an unknown user on 12/01/2005)
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It is what I need to use WMI. And the links is useful for me
 
Comment #12  (Posted by an unknown user on 12/02/2005)
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Excellent article. Very well written.
 
Comment #13  (Posted by Andy Bonner (aka Skullcrusher) on 12/04/2005)
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Just found another port that needed to be allowed on XP SP2.

TCP Port 1038 - Message Tracking Query Protocol
 
Comment #14  (Posted by Benjamin Lindelof on 12/09/2005)
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Unable to follow the author.
 
Comment #15  (Posted by an unknown user on 12/09/2005)
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No method to read the Arrays in WMI?
 
Comment #16  (Posted by an unknown user on 12/09/2005)
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No method to read the Arrays in WMI?
 
Comment #17  (Posted by Benjamin Lindelof on 12/09/2005)
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I found the bug. Instead of:
myManagementScope = New System.Management.ManagementScope("\" & _
It should say:
myManagementScope = New System.Management.ManagementScope("\\" & _

 
Comment #18  (Posted by an unknown user on 12/12/2005)
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The article is very good. However, I can't figure out how to download the code. I have searched the following page and can't find the word "download" or anything tat looks like a download link for the ConnectionTester referenced on page 5 of the article:

http://www.devcity.net/Articles/144/6/article.aspx

Thanks!
 
Comment #19  (Posted by an unknown user on 12/12/2005)
Rating
The article is very good. However, I can't figure out how to download the code. I have searched the following page and can't find the word "download" or anything tat looks like a download link for the ConnectionTester referenced on page 5 of the article:

http://www.devcity.net/Articles/144/6/article.aspx

Thanks!
 
Comment #20  (Posted by an unknown user on 12/25/2005)
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Many thanks, you saved me a lot of time (and maybe grey hairs ^^)!
 
Comment #21  (Posted by an unknown user on 12/25/2005)
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To look at additional WMI classes, see the wbemtest.exe tool located on any system with WMI installed. Just goto Start --> Run, then type "wbemtest", then connect to the "root\cimv2" (or a different) namespace, click Enum Classes --> Recursive!
 
Comment #22  (Posted by Bhaskar on 01/20/2006)
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Thanks for the fruitful efforts made !

This code works very well when the servername/IP Address is "localhost"/127.0.0.1

When i give Servername as one of the systems in the LAN it gives:
"Connecting to {0}DevServer{0}DevServer is online with IP address: {1}192.168.1.25.Error while connecting to {0}DevServer: {1}Access denied"

This is the case with all the systems in my LAN.
Please help!!!
 
Comment #23  (Posted by an unknown user on 01/21/2006)
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Either I am blind or there is no link to download this code. I am exited about it, but am also frustrated that I cannot download it :(
 
Comment #24  (Posted by Kevin on 01/29/2006)
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Why is there no remoting example using early binding. All that is said is that mgmtclassgen.exe can be used to make WMI strongly typed.
 
Comment #25  (Posted by an unknown user on 02/02/2006)
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great
 
Comment #26  (Posted by an unknown user on 02/11/2006)
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Well, I was looking for this information and, wow, I found much more than I expected. Great job! Hopefully your grey hair turn back! ;)
 
Comment #27  (Posted by an unknown user on 03/09/2006)
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just easy too read - keep on goin'
 
Comment #28  (Posted by an unknown user on 03/09/2006)
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Excellent tutorial! The download is difficult to find, but not the authors fault. Works great. There is one mistake in the first page example as mentioned already, missing a \. Should be \\. Anyway, great stuff, the class is awesome!
 
Comment #29  (Posted by an unknown user on 03/13/2006)
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I find this article easy to understand, it's perfect for a beginner like me searching to get the best from WMI
 
Comment #30  (Posted by an unknown user on 03/31/2006)
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Felicitaciones.
Es un articulo facil de entender para los desarrolladores de otros idiomas.

Deben cambiar el link de:

WMI Administrative Tools (including CIM studio)

a:


http://www.microsoft.com/downloads/details.aspx?FamilyID=6430f853-1120-48db-8cc5-f2abdc3ed314&DisplayLang=en

Oscar José Lofrano Maturi
ojlofranom@msn.com
MCP VB.NET Windows Application
Venezuela
 
Comment #31  (Posted by Someone on 04/18/2006)
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Great article! But there is a bug in the function ExecWmiQuery ;) It does not work for a remote Win2003 machine that requires login. Instead of

_ManagementSearcher = New System.Management.ManagementObjectSearcher(_ManagementScope.Path.ToString, cWmiQuery) ' bug: this will cause a new ManagementScope object to be created, when the correct ManagementScope object already exists

Use:

Dim query As New ObjectQuery(cWmiQuery)
_ManagementSearcher = New System.Management.ManagementObjectSearcher(_ManagementScope, query)

Your code creates a new instance of ManagementScope and does not set the UserName and Password connection options. Instead use the existing _ManagementScope variable which does have the username and password set already! :)

 
Comment #32  (Posted by an unknown user on 04/20/2006)
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A superb article to newbies of WMI like me but i want more info for remote connections,that code wont work in XP Machines and Server 2003
 
Comment #33  (Posted by an unknown user on 05/09/2006)
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interesting
 
Comment #34  (Posted by Stuart Nathan on 06/27/2006)
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When I run your example, I get the error message "RPC Server is unavailable" when I try to connect to another machine.
 
Comment #35  (Posted by an unknown user on 06/30/2006)
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Very interesting article about the link between scripting & vb.net.Tnx!
 
Comment #36  (Posted by an unknown user on 07/06/2006)
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Excelentemente explicado. De mucha utilidad y muy claro.
 
Comment #37  (Posted by an unknown user on 07/23/2006)
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Very well written article. Easy to follow and informative. Thank you.
 
Comment #38  (Posted by an unknown user on 07/26/2006)
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Easy to read, easy to understand.
Great article for someone starting out!
 
Comment #39  (Posted by sovannborith on 08/17/2006)
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my computer does not have system.Management namespace. how can i get it. please reply

 
Comment #40  (Posted by an unknown user on 08/19/2006)
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Breath of fresh air on the subject. I only wish that my web searches hit on the article sooner.
 
Comment #41  (Posted by an unknown user on 10/05/2006)
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Great Job!! Thanks a lot
 
Comment #42  (Posted by Muhammad Aamir Hassan on 10/11/2006)
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i really enjoyed this snipt. May God help you

aamir
 
Comment #43  (Posted by Lesh Augustus on 11/02/2006)
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Set System Information or Set System Environment Variable in VB.Net
===================================================

Dim objEv As ManagementObjectSearcher = New ManagementObjectSearcher("SELECT * FROM Win32_Environment")
For Each objMgmt As ManagementObject In objEv.Get
If objMgmt("Name") = "Path" And objMgmt("UserName") = "" Then
Dim strPath As String = objMgmt("VariableValue")
If strPath.ToLower.IndexOf("cvsnt") >= 0 Then
If objMgmt("VariableValue").ToString.Substring(objMgmt("VariableValue").ToString.Length - 1) = ";" Then
objMgmt("VariableValue") = objMgmt("VariableValue") + Trim(txtNewPath.Text) + ";"
Else
objMgmt("VariableValue") = objMgmt("VariableValue") + ";" + Trim(txtNewPath.Text) + ";"
End If
End If
objMgmt.Put()
MessageBox.Show("Path Added Successfully")
End If
Next
 
Comment #44  (Posted by PK on 12/22/2006)
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Hi, I couldn't find the link to the ConnectionTester class?
 
Comment #45  (Posted by an unknown user on 03/12/2007)
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Thanks buddy, very good article
 
Comment #46  (Posted by zmrcic on 03/14/2007)
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I'm using wmi and I think its great article. I have new problem. Can I look into printer setup (emulation, characteset....) by wmi?
 
Comment #47  (Posted by an unknown user on 05/25/2007)
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Hi Mr. Martin

Great article! But could you help me with the Access is Denied error? i'm trying to connect to a remote computer and it returns an online status but i can't access it. I think it's the rpc or something. AT CheckForWMI procedure, the error is in the else statement of the code below.

Catch e1 As Exception
'* USUALLY indicates remote RPC server is not online
If e1.Message.IndexOf("RPC-server") <> -1 Then
'* Do not set _HasErrors in this case
'* as that could be interpreted as being off-line
_ErrorMessage = e1.Message
Else
_HasErrors = True
_ErrorMessage = e1.Message
End If

i really need help please!
thanks!!
 
Comment #48  (Posted by Ashu on 10/09/2007)
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Thank you very much for this article, WMI isn't exactly simple to access outside of say VBSCripting realm. :)

Anyway, I am not able to get the ConnectionTesterClass to work for some reason, I am using VB.NET 2005 Express edition and it says the System.Net has been obsolete...any idea how i Can go about resolving this?

Thanks again!
 
Comment #49  (Posted by Amit Ashok Pawar. on 12/17/2007)
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Artical was nice. I got help from this artical. but your code is constantly giving me an error like Access is Denied. I'm using XP Service pack 2 (Professonal)Please help me.
 
Comment #50  (Posted by an unknown user on 02/10/2008)
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Excellent Article. Thank you for writing this up.

I did find a problem though. The Win32_Product class has a prblem on Windows Vista. It's scheduled to be fixed in SP1.

On another note, I parsed all of the errors in the event log in the last 15 days. The date/time WMI returns is UGLY (20080210185042.0000000-000). I wrote it out with following lines of code:

Console.WriteLine("Date: {0}", Left(mo.GetPropertyValue("TimeGenerated").ToString, 4) & _
"-" & Mid(mo.GetPropertyValue("TimeGenerated").ToString, 5, 2) & _
"-" & Mid(mo.GetPropertyValue("TimeGenerated").ToString, 7, 2))
Console.WriteLine("Time (GMT): {0}", Mid(mo.GetPropertyValue("TimeGenerated").ToString, 9, 2) & _
":" & Mid(mo.GetPropertyValue("TimeGenerated").ToString, 11, 2) & _
":" & Mid(mo.GetPropertyValue("TimeGenerated").ToString, 13, 2))

DO you know if there's an easier way to reformat the date/time?

Thanks again for the article. It's exactly what I was