April 11, 2014 | Posted in: .Net

DirectorySearcher.FindAll() is very slow. Instead search for the specific AD user, much faster:

Dim windowsLogin As String
Dim currentIdentity As System.Security.Principal.WindowsIdentity
Dim slashIndex As Integer = 0

Try
currentIdentity = System.Security.Principal.WindowsIdentity.GetCurrent()
slashIndex = currentIdentity.Name.IndexOf(“\”)
windowsLogin = currentIdentity.Name.Substring(slashIndex + 1)
Catch
Throw
End Try

Dim searcher As New DirectorySearcher(“”)
Dim result As SearchResult = Nothing
With searcher
.Filter = String.Format(“(&(objectCategory=person)(SAMAccountName={0}))”, windowsLogin)
result = .FindOne()
End With

If ((result IsNot Nothing) AndAlso
(result.Properties.Item(“SAMAccountName”) IsNot Nothing) AndAlso
(result.Properties.Item(“SAMAccountName”).Item(0) IsNot Nothing) AndAlso
(CStr(result.Properties.Item(“SAMAccountName”).Item(0)).ToUpper() = windowsLogin.ToUpper())) Then

MessageBox.Show(String.Format(“User {0}”, windowsLogin) + ” found”)

End If