public LinqWindow() { InitializeComponent(); if (bl == null) { bl = new BL_imp(); } list = MyFunctions.ChildWhithoutContract(); list1 = MyFunctions.NannyByTAMAT(); ChildwithoutContract.ItemsSource = list; NannyByTMT.ItemsSource = list1; foreach (var mo in bl.getMotherList()) //show the mothers { ComboBoxItem item = new ComboBoxItem(); item.Content = "ID: " + mo.Id + ", First Name: " + mo.FirstName + ", Last Name: " + mo.LastName; motherDistanceComboBox.Items.Add(item); } backgroundWorker = new BackgroundWorker(); backgroundWorker.DoWork += BackgroundWorker_DoWork; backgroundWorker.RunWorkerCompleted += BackgroundWorker_RunWorkerCompleted; backgroundWorker.WorkerSupportsCancellation = true; }