private void tbnAssignEmployee_Click(object sender, RoutedEventArgs e) { if (comboShopsLoanedID.SelectedValue != null && comboShopsLoanedID.SelectedValue != null) { int fid1 = int.Parse(comboShopsLoanedID.SelectedValue.ToString()); int fid = int.Parse(comboEmployeeNotAssigned.SelectedValue.ToString()); connection.AssignEmployee(fid1, fid); MessageBox.Show("Assign succeesfully"); } else { MessageBox.Show("Enter the information"); } }