private void returnButton_Click(object sender, EventArgs e) { try { if ((int)returnComboBox.SelectedValue != null) { int affectedRows = mediaLogic.DeleteBorrow((int)returnComboBox.SelectedValue); } } catch (Exception ex) { MessageBox.Show("Nothing to return"); } returnComboBox.DataSource = mediaLogic.ListReturn(CurrentUser.UserID); returnComboBox.DisplayMember = "PairName"; returnComboBox.ValueMember = "PairId"; returnComboBox.Text = ""; }