private void cmbx_projects_SelectedIndexChanged(object sender, Telerik.WinControls.UI.Data.PositionChangedEventArgs e) { checkedListBoxWorkers.Items.Clear(); int idPprojectSelect = (cmbx_projects.SelectedItem.Tag as Project).ProjectId; List <User> workers = UserRequests.getWorkerNotInProject(idPprojectSelect); if (workers != null) { checkedListBoxWorkers.DisplayMember = "UserName"; foreach (User worker in workers) { checkedListBoxWorkers.Items.Add(getItemWorker(worker)); } } }