private void btnCalculate_Click(object sender, RoutedEventArgs e) { history = new HistoryViewModel(); DateTime date = DateTime.Today; int day = date.Day; int month = date.Month; int year = date.Year; string myDate = day + "//" + month + "//" + year; applianceViewModel = new ApplianceViewModel(); CURRENT_UNITS = Convert.ToDouble(txtCurrentUnits.Text); double total_units = 0; string appliance1 = txtAppliance1Hours.Text; string appliance2 = txtAppliance2Hours.Text; string appliance3 = txtAppliance3Hours.Text; string appliance4 = txtAppliance4Hours.Text; string appliance5 = txtAppliance5Hours.Text; try { double first_appliance_hours = Convert.ToDouble(appliance1); double second_appliance_hours = Convert.ToDouble(appliance2); double third_appliance_hours = Convert.ToDouble(appliance3); double fourth_appliance_hours = Convert.ToDouble(appliance4); double fifth_appliance_hours = Convert.ToDouble(appliance5); double total_appliance_hours = first_appliance_hours + second_appliance_hours + third_appliance_hours + fourth_appliance_hours + fifth_appliance_hours; Kilo_Watts = (total_watts * total_appliance_hours) * tota_number; total_units = Kilo_Watts / 1000; REMAINING_UNITS += CURRENT_UNITS - total_units; string checkDate = date.ToString("D"); history.saveHistory(tota_number, total_units, REMAINING_UNITS, checkDate); lblRemainingUnits.Text = "You have " + REMAINING_UNITS + " Units Remaining"; messageBox("Total consumed Units for selected appliances is : " + total_units + " units"); } catch (Exception ex) { messageBox("Please check your text fields or " + ex.Message); } }