A little recursion might help :
public void GetFoldersInFolder(OutLook.MAPIFolder folder)
{
foreach (OutLook.MAPIFolder subFolder in folder.Folders)
{
if (!nbFolder.Items.Contains(subFolder.Name))
{
nbFolder.Items.Add(subFolder.Name);
GetFoldersInFolder(subFolder);
}
}
}
Incorporate this in your "LoadEmailFolderCombo" method.
Cheers