Archived Development Uncategorized

VB.NET – List active directory users – Re-write

Please note: This is a rewrite of an article I wrote way back in 2007. The original article has been updated with a link to this one.

As per usual I had a situation where I had to do some Active Directory stuff with VB.NET. I had to grab a list of all the users in our AD so that people could select a user and perform functions on them from within a webpage.
Another note: This article is VB.NET-specific. If you’d like to know how to do this using C# please see this post’s “partner” entitled “Follow Up – List active directory users – This time in C#”

Carrying on though, there are a number of ways you can do this but in the .NET Framework they all involve using the System.DirectoryServices namespace. A couple of quick things to be aware of before you try this yourself:

  • Before messing with your Active Directory make sure you know what you’re doing and have the permissions of your AD Administrators (if it’s not you!)
  • If you are going to use any of the following code from a .NET console application you’ll need to add a reference to System.DirectoryServices in addition to importing the namespace. I wrote a post a while ago about this entitled “Developer Dumbness” – it has the steps you need to add a reference to a .NET console application.

Anyway, the code below is a simple function that queries your Active Directory domain and retrieves all the user objects. This particular example filters out any user account whose “DisplayName” attribute meets the following criteria (the requirements for the app I had to write):

  • Has an email address
  • Does not contain the “$” symbol
  • Does not contain the words “Admin” or “admin”
  • Does not contain the words “Test” or “test”
  • Does not contain the words “Service” or “service”
  • Does not contain the word “System” or “system”

The example code below is a complete Windows console application that does all of the above. It’s important to note that if you’re using this in a production environment you’ll need to make sure the application containing the code has access to the Active Directory, usually using .NET impersonation – this is beyond the scope of this post.

List Active Directory Users in VB.NET:

Imports System
Imports System.Collections.Generic
Imports System.DirectoryServices

Module ListAdUsers

    Sub Main(ByVal ParamArray Args() As String)

        Dim userList As List(Of String) = New List(Of String)

        Dim badEntries As Integer = 0
        Dim domainName As String = String.Empty

        If (Args.Length > 0) Then
            domainName = Args(0)
            Console.Write(String.Format("{0}Please enter your Active Directory domain name: ", vbCrLf))
            domainName = Console.ReadLine()
        End If

        Console.Write(String.Format("{0}Attempting to build user list for {1} ...{0}{0}", vbCrLf, domainName))

            If Not String.IsNullOrEmpty(domainName) Then
                Dim myDirectoryEntry As DirectoryEntry = New DirectoryEntry(String.Format("LDAP://{0}", domainName))
                Dim mySearcher As DirectorySearcher = New DirectorySearcher(myDirectoryEntry)
                Dim mySort As SortOption = New SortOption("sn", SortDirection.Ascending)
                mySearcher.Filter = ("(objectClass=user)")
                mySearcher.Sort = mySort
                For Each resEnt As SearchResult In mySearcher.FindAll()
                        If Not String.IsNullOrEmpty(resEnt.Properties("Mail")(0).ToString()) _
                            AndAlso System.Text.RegularExpressions.Regex.IsMatch(resEnt.Properties("DisplayName")(0).ToString(), " |admin|test|service|system|[$]", System.Text.RegularExpressions.RegexOptions.IgnoreCase) Then
                            Dim space As Integer = resEnt.Properties("DisplayName")(0).ToString().IndexOf(" ")
                            Dim formattedName As String = String.Format("{0}{1}{2}", _
                                                                        resEnt.Properties("DisplayName")(0).ToString().Substring(space).PadRight(25), _
                                                                        resEnt.Properties("DisplayName")(0).ToString().Substring(0, space).PadRight(15), _
                                                                        resEnt.Properties("Mail")(0).ToString() _
                        End If
                        badEntries = badEntries + 1
                    End Try
                If (userList.Count > 0) Then
                    Console.WriteLine(String.Format("=========== Listing of users in the {0} domain{1}", domainName, vbCrLf))
                    Console.WriteLine(String.Format("{0}{1}{2}{3}", "Surname".PadRight(25), "First Name".PadRight(15), "Email Address", vbCrLf))
                    For i = 0 To userList.Count - 1
                    Console.WriteLine(String.Format("{0}=========== {1} users found in the {2} domain", vbCrLf, userList.Count.ToString(), domainName))
                    Console.WriteLine(String.Format("{0}=========== 0 users found in the {1} domain", vbCrLf, userList.Count.ToString()))
                End If
                Console.WriteLine(String.Format("=========== {0} objects could not be read", badEntries.ToString()))
                Console.WriteLine("=========== End of Listing")
                Console.WriteLine("Please enter a domain name next time!")
            End If
        Catch ex As Exception
            ' in a production app you wouldn't show the user the exception details
            Console.Write(String.Format("A critical error occurred.{0}Details: {1}", vbCrLf, ex.Message.ToString()))
        End Try
    End Sub

End Module

There are a HEAP of attributes you can use instead of “sn” in the sample above. Personally I use ADSIEDIT.MSC to look at all the possible attributes but you’ll need domain administrative access to run that. Here are a couple of useful ones though …

  • company
  • department
  • description
  • displayName
  • mail
  • manager
  • name
  • givenName
  • sAMAccountName

Hope that helps someone! 🙂

Archived Development Uncategorized

List active directory users – C#

In this article I’m going to carry on with the follow-ups to posts I wrote in the past about various topics. Today’s topic is still on the subject of using .NET to list the users in Active Directory although this time we’re going to do it in C#. I wrote the first post and sample application using VB.NET back when I (perhaps) didn’t know as much as I know now … hopefully y’all won’t be too harsh on my n00b code from back then. 🙂

So, what’s different? Apart from the language change here is a summary of what’s changed between this version and the original.

  • All references that aren’t needed have been removed.
  • The results are now added to a generic list of strings (the original was just an ArrayList).
  • The domain name can now be passed as a parameter on the command line. If one isn’t provided the user will be prompted.
  • Regular expressions are now used to filter out user accounts that don’t match certain criteria (the original did some horribly repetitive case-sensitive matching).
  • The output is now formatted better (the original was just a plain list).
  • The account’s email address is now shown too.
  • A total count of the accounts that can’t be ‘read’ is shown at the end.
  • The app’s exception handling is a whole heap better (the original, being a sample, didn’t have any).
  • The app won’t run if a domain name isn’t provided at all – an error message is displayed.

Note that this version doesn’t do any validation of the domain name e.g. length, illegal characters etc although you could use regular expressions to validate it.

On the next page is the entire source for the application – it’s a single .cs file.

Archived Development Uncategorized

Using XPathNavigator to query XML files

Have you ever needed to query a specific key value in an XML file? Depending on the format of your XML file, here’s how to do it using XPathNavigator.

This is something I planned to write about ages ago but never got around to it.


The System.Xml.XPath Namespace has some pretty useful stuff in it. This article is going to cover how to use both VB.NET and C# to extract a particular key value from an XML file. Let’s say you have a simple XML file called C:MyApplicationConfiguration.xml that stores configuration for your application. It looks like the sample below.


<?xml version="1.0" encoding="utf-8" standalone="yes"?>

The code – C#

First up, let’s look at the C# code to read the value of the "BackupServer" key from the file above.

Read a key using C#”:

XPathDocument document = new XPathDocument("C:\MyApplication\Configuration.xml");
XPathNavigator navigator = document.CreateNavigator();

XPathNavigator currentNode = navigator.SelectSingleNode("//My.Application.Config/Settings/BackupServer");
String backupServer = currentNode.InnerXml.ToString();

The code – VB.NET

Read a key using VB.NET:

Dim document As XPathDocument = New XPathDocument("C:MyApplicationConfiguration.xml")
Dim navigator As XPathNavigator = document.CreateNavigator()

Dim currentNode As XPathNavigator =
Dim backupServer As String = currentNode.InnerXml.ToString()

That’s it! Pretty simple really. 🙂

Archived Development Uncategorized

C# – Self updating application …

Disclaimer: I wrote this code way back in 2007 and I reckon I’ve learnt a fair bit since then (not being a professional developer).  Go easy on me if you feel like commenting on the code itself.  🙂

This one might be interesting for people who have wondered about how to distribute the latest version of their application without having to tell people when an update is released.

There are built-in options that you can use with the Microsoft .NET platform such as ClickOnce. We use ClickOnce here at Trade Me to deploy some of our in-house applications and it works really well.

Recently, though, I thought “Why not see if I can write my own method of updating my application?” It turned out to be quite an interesting litte project! The application I was working on at the time is written in C# although the learning curve to go from VB.NET to C# or vice-versa isn’t too steep.

Where do we start?

To begin with I decided the update process should have the following steps.

  • Check my website for a text file containing version information.
  • Read the version information text file and compare the version information in it to the version of the application currently running.
  • If the version in the text file is the same or less than the version currently being run, do nothing other than show a message to the user.
  • If the version in the text file is greater than the version currently being run ask the user if they want to update to the later version.
  • Do the actual update.


There are 2 components to this particular solution. The first part is the actual application being updated and the updater application. If you are going to follow along with any of the stuff in this article you’ll need to start a new solution with 2 projects. My main project is called “CountDown” and the updater application is called “AppStart” (for reasons not related to the updating stuff here). For the purposes of this article I’m going to assume you have a single project that needs the update functionality.

The main application

The first thing your main application will need to do is make use of the System.Net namespace by adding the following line to the top of the main namespace file.


using System.Net;

When the user runs the application they can click a button that runs a method to do most of the steps above. The first thing the method does is try to resolve the IP address of my website ( resolves to

Resolve IP Address:

  string RemoteDomain = "";
  IPHostEntry inetServer = Dns.GetHostEntry(RemoteDomain.Replace("http://", String.Empty));
catch (Exception ex)
Archived Development Uncategorized

Full-screen Windows app using VB.NET

Recently I had to write a Windows application that required the main form to run in full-screen mode. This means no title bar and with the window appearance above everything else, i.e. Start Button, taskbar, system tray and all other apps.

This requires an API call to the SetWindowPos function which you need to create an alias to before you can call it. The first part of the code, which should be placed in the declarations part of the form, looks like this :

SetWindowsPos alias:

Private Declare Function SetWindowPos Lib "user32.dll" Alias "SetWindowPos" (ByVal hWnd As IntPtr, ByVal hWndIntertAfter As IntPtr, ByVal X As Integer, ByVal Y As Integer, ByVal cx As Integer, ByVal cy As Integer, ByVal uFlags As Integer) As Boolean

You also need an alias to the API function called GetSystemMetrics, like this :

VB.NET – GetSystemMetrics alias:

Private Declare Function GetSystemMetrics Lib "user32.dll" Alias "GetSystemMetrics" (ByVal Which As Integer) As Integer

Following this you need to declare 4 constants :

Required constants:

Private Const SM_CXSCREEN As Integer = 0
Private Const SM_CYSCREEN As Integer = 1
Private Shared HWND_TOP As IntPtr = IntPtr.Zero
Private Const SWP_SHOWWINDOW As Integer = 64

Then 2 public properties :

Required property #1:

Public ReadOnly Property ScreenX() As Integer
        Return GetSystemMetrics(SM_CXSCREEN)
    End Get
End Property

-- and --

Required property #2:

Public ReadOnly Property ScreenY() As Integer
        Return GetSystemMetrics(SM_CYSCREEN)
    End Get
End Property

After this you need to write a simple sub routine to use the constants you declared above and that calls the SetWindowPos API function. The function's code looks like this :

The FullScreen() method:

Private Sub FullScreen()
    Me.WindowState = FormWindowState.Maximized
    Me.FormBorderStyle = FormBorderStyle.None
    Me.TopMost = True
    SetWindowPos(Me.Handle, HWND_TOP, 0, 0, ScreenX, ScreenY, SWP_SHOWWINDOW)
End Sub

Beyond that it's just a case of calling the FullScreen sub routine whenever you want the application to show in full-screen mode. Easy huh? 🙂