Question

I have a combobox bound to a datatable that I fill with user’s names from active directory. This code takes about a minute to complete. Is there a better way that I am missing?

Function users() As DataTable
    Dim dt As DataTable
    Dim dr As DataRow
    Dim idCoulumn As DataColumn
    Dim nameCoulumn As DataColumn

    Dim dirEntry As New System.DirectoryServices.DirectoryEntry("LDAP://CN=Users,DC=myDomain,DC=local")

    Dim oSearcher As DirectorySearcher = New DirectorySearcher(dirEntry)
    Dim oResults As SearchResultCollection

    oSearcher.PropertiesToLoad.Add("samAccountName")
    oSearcher.PropertiesToLoad.Add("givenname")
    oSearcher.PropertiesToLoad.Add("sn")
    oSearcher.PropertiesToLoad.Add("cn")
    oSearcher.Filter = "objectCategory=person"
    oResults = oSearcher.FindAll

    dt = New DataTable()
    idCoulumn = New DataColumn("ID", Type.GetType("System.String"))
    nameCoulumn = New DataColumn("Name", Type.GetType("System.String"))

    dt.Columns.Add(idCoulumn)
    dt.Columns.Add(nameCoulumn)

    For Each oResult In oResults
        With oResult.GetDirectoryEntry()
            If .Properties("cn").Value <> "" AndAlso .Properties("samAccountName").Value <> "" AndAlso .Properties("sn").Value <> "" Then
                dr = dt.NewRow()
                dr("ID") = .Properties("samAccountName").Value
                dr("Name") = String.Format("{0},{1} : {2}", .Properties("sn").Value, .Properties("givenname").Value, .Properties("samAccountName").Value)
                dt.Rows.Add(dr)
            End If
        End With
    Next

    dt.DefaultView.Sort = "Name"

    Return dt

End Function

Answer 1

@Spevy helped me get to this solution with his proposed answer.

I changed my Directory entry to:

Dim dirEntry As New System.DirectoryServices.DirectoryEntry("LDAP://myDomain")

I set my search filter:

oSearcher.Filter = "(&(objectCategory=user)(objectClass=user))"

And changed my if statement to:

If .Properties("samAccountName").Value <> "" AndAlso .Properties("sn").Value <> "" Then

I am not sure what adding these lines of code really do but I get the same results whether they are there or not, so I removed them:

oSearcher.PropertiesToLoad.Add("samAccountName")
oSearcher.PropertiesToLoad.Add("givenname")
oSearcher.PropertiesToLoad.Add("sn")
oSearcher.PropertiesToLoad.Add("cn")