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);
            }
        }