private void HostOccupancyButtom_Click(object sender, RoutedEventArgs e) { bool flag = false; List <Host> mylist = bl.GetHostsList(); foreach (var item in mylist) { if (HostOccupancyTextBox.Text == item.HostId) { flag = true; } } if (flag) { float temp = bl.GetAnnualBusyPercentageForAllUnitsForOneHost(HostOccupancyTextBox.Text); answerHostOccupancyTextBlock.Text = "The occupancy of this host is: " + temp; } else { string titel = "Oops"; string err = "Cannot find a Host with this ID."; MessageBox.Show(err, titel); } }