Problem using a global variable in an LDAP request

Question

My goal is to retrieve the OU names from an LDAP directory and according to each OU name display its sub OU. All this in C# with a WPF interface. My OU retrieval function is ok but the problem is with the display function of the sub OUs according to the chosen OU. I use a global variable and I think the problem comes from there but I don't really know why. If you know why I'm in :) I am available for any question. Thanks

Maxime

There is the code :

namespace WpfApp1
{
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        comboBoxEntite.ItemsSource = OUList;
        afficherOuEntite();
        comboBoxSousEntite.ItemsSource = subOuList;
        afficherOuSousEntite();
    }

    private void btnMinimize_Click(object sender, RoutedEventArgs e)
    {
        WindowState = WindowState.Minimized;
    }
    private void btnClose_Click(object sender, RoutedEventArgs e)
    {
        Application.Current.Shutdown();
    }
    private void Window_MouseDown(object sender, MouseButtonEventArgs e)
    {
        if (e.LeftButton == MouseButtonState.Pressed)
            DragMove();
    }

    public void ComboBoxEntite_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)
    {
        selectedItemF = "LDAP://myserver.lan/OU=" + comboBoxEntite.SelectedItem.ToString() + ",OU=MPG-Users,DC=myserver,DC=lan";
        TB.Text = selectedItemF;
    }

    public void afficherOuEntite()
    {
        string ldapServer = "LDAP://myserver.lan/OU=MPG-Users,DC=myserver,DC=lan";
        DirectoryEntry myLdapConnection = new DirectoryEntry(ldapServer);
        DirectorySearcher myDirectorySearcher = new DirectorySearcher(myLdapConnection);
        myDirectorySearcher.Filter = "(objectClass=organizationalUnit)";
        myDirectorySearcher.PropertiesToLoad.Add("Name");
        myDirectorySearcher.SearchScope = SearchScope.OneLevel;
        SearchResultCollection resultsOuEntite = myDirectorySearcher.FindAll();

        foreach (SearchResult result in resultsOuEntite)
        {
            string ouName = result.Properties["Name"][0].ToString();
            OUList.Add(ouName);
        }
    }

    public void afficherOuSousEntite()
    {
        DirectoryEntry myLdapConnection = new DirectoryEntry(selectedItemF);
        DirectorySearcher myDirectorySearcher = new DirectorySearcher(myLdapConnection);
        myDirectorySearcher.Filter = "(objectClass=organizationalUnit)";
        myDirectorySearcher.PropertiesToLoad.Add("Name");
        myDirectorySearcher.SearchScope = SearchScope.OneLevel;
        SearchResultCollection resultsOuSousEntite = myDirectorySearcher.FindAll();

        foreach (SearchResult result in resultsOuSousEntite)
        {
            string ouName = result.Properties["Name"][0].ToString();
            subOuList.Add(ouName);
        }
    }
    public List<string> OUList = new List<string>();
    public List<string> subOuList = new List<string>();

    public static string selectedItemF;
}
}

The result I have concerning the sub-OR is an empty result, as if the search was not based on anything