using DevExpress.XtraScheduler;

private void schedulerDataStorage1_FilterResource(object sender, PersistentObjectCancelEventArgs e) {
    SchedulerDataStorage storage = (SchedulerDataStorage) sender;
    Resource res = (Resource) e.Object;
    // Shows the first three resources in the collection.
    e.Cancel = storage.Resources.Items.IndexOf(res) > 2 ;
}

Imports DevExpress.XtraScheduler

Private Sub schedulerDataStorage1_FilterResource(ByVal sender As Object, ByVal e As PersistentObjectCancelEventArgs)
    Dim storage As SchedulerDataStorage = CType(sender, SchedulerDataStorage)
    Dim res As Resource = CType(e.Object, Resource)
    ' Shows the first three resources in the collection.
    e.Cancel = storage.Resources.Items.IndexOf(res) > 2
End Sub