//method to read the list of customer data from a file to the listbox
public static List <Customer> ReadCustomers()
{
List <Customer> customers = new List <Customer>(); //create empty list
Customer customer; // reading customers
string line; // next line from the file
string[] fields; // line broken into fields
int accountNo = 0;
string customerName = "";
string customerType = "";
decimal chargeAmount;
//uses filestream to read the file
using (FileStream fileStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read))
{
using (StreamReader streamReader = new StreamReader(fileStream))
{
//continues reading until the end of file is reached.
while (!streamReader.EndOfStream)
{
line = streamReader.ReadLine();
fields = line.Split(','); // split on commas
//asign the data to variables
accountNo = Convert.ToInt32(fields[0]);
customerName = fields[1];
customerType = fields[2];
chargeAmount = Convert.ToDecimal(fields[3]);
//checking which customer is in the read line.
if (fields[2] == "R")
{
customer = new ResidentialCustomer(accountNo, customerName, customerType, chargeAmount);
}
else if (fields[2] == "C")
{
customer = new CommercialCustomer(accountNo, customerName, customerType, chargeAmount);
}
else
{
customer = new IndustrialCustomer(accountNo, customerName, customerType, chargeAmount);
}
customers.Add(customer);
}
}
}
return(customers);
}
// calculate customer charge
public virtual decimal CalculateCharge()
{
// customer charge passed to customer type objects
if (this.customerType == 'R')
{
Customer c = new ResidentialCustomer(accountNo, customerName, customerType, kwh1, kwh2);
return(c.CalculateCharge());
}
else if (this.customerType == 'C')
{
Customer c = new CommercialCustomer(accountNo, customerName, customerType, kwh1, kwh2);
return(c.CalculateCharge());
}
else if (this.customerType == 'I')
{
Customer c = new IndustrialCustomer(accountNo, customerName, customerType, kwh1, kwh2);
return(c.CalculateCharge());
}
return(0);
}
private void CalculateBillbutton_Click(object sender, EventArgs e)
{
//this event perform all bill calculation using seperate methods for different customer type
//string customerInput = (CustomerTypecomboBox1.Text);
decimal kwhUsedPerCustomer = decimal.Parse(KwhTextBox1.Text.Trim()); //converting customer input text to double to perform calculations
string customerName = customerNameTextBox1.Text.Trim();
int customerAccountNum;
//this try catch block handles the exception created
//if the user tries to calculate the bill without inserting valid account number
try
{
customerAccountNum = int.Parse(accountNumberTextBox.Text.Trim());
}
catch (FormatException)
{
MessageBox.Show($"Invalid Account number, please insert your account number.");
return;
}
//in this try catch block the calculate bill is performed
//based on the selected item/index by the user
//objects are created as instances of sub classes depending on the selection by the customer
try
{
switch (CustomerTypecomboBox1.SelectedItem)
{
case "Residential":
ResidentialCustomer rcust = new ResidentialCustomer(customerAccountNum, customerName, "R");
rcust.ChargeAmount = rcust.CalculateCharge(kwhUsedPerCustomer);
EstimatedBillLabel.Text = "Estimated Bill: " + rcust.ChargeAmount.ToString("C");
break;
case "Commercial":
CommercialCustomer cCustomer = new CommercialCustomer(customerAccountNum, customerName, "C");
cCustomer.ChargeAmount = cCustomer.CalculateCharge(kwhUsedPerCustomer);
EstimatedBillLabel.Text = "Estimated Bill: " + cCustomer.ChargeAmount.ToString("C");
break;
case "Industrial":
decimal offpeakKwhUsedPerCustomer = decimal.Parse(OffpeakKwhTextBox1.Text.Trim());
IndustrialCustomer indCustomer = new IndustrialCustomer(customerAccountNum, customerName, "I");
indCustomer.ChargeAmount = indCustomer.CalculateCharge(kwhUsedPerCustomer, offpeakKwhUsedPerCustomer);
EstimatedBillLabel.Text = "Estimated Bill: " + indCustomer.ChargeAmount.ToString("C");
break;
default:
MessageBox.Show("Something went wrong bill could not be estimated");
break;
}
//eraseTextField();
}
catch (ArgumentException excp)
{
MessageBox.Show($"Unable to create new customer invalid information. {excp.Message}");
return;
}
catch (FormatException excp)
{
MessageBox.Show($"Non numeric data in a numeric field. {excp.Message}");
return;
}
}
//this event adds the customer details into the list box
private void AddCustomerButton_Click(object sender, EventArgs e)
{
decimal kwhUsedPerCustomer = decimal.Parse(KwhTextBox1.Text.Trim()); //converting customer input text to double to perform calculations
string customerName = customerNameTextBox1.Text.Trim();
int customerAccountNum;
//this try catch block handles the exception created
//if the user tries to calculate the bill without inserting valid account number
try
{
customerAccountNum = int.Parse(accountNumberTextBox.Text.Trim());
}
catch (FormatException)
{
MessageBox.Show($"Invalid Account number, please insert your account number.");
return;
}
Customer c = null;
//Based the on user's selection in the combo box
// a new customer object is created
try
{
if (CustomerTypecomboBox1.SelectedIndex == 0)
{
c = new ResidentialCustomer(customerAccountNum, customerName, "R");
c.ChargeAmount = c.CalculateCharge(kwhUsedPerCustomer);
}
else if (CustomerTypecomboBox1.SelectedIndex == 1)
{
c = new CommercialCustomer(customerAccountNum, customerName, "C");
c.ChargeAmount = c.CalculateCharge(kwhUsedPerCustomer);
}
else
{
decimal offpeakKwhUsedPerCustomer = decimal.Parse(OffpeakKwhTextBox1.Text.Trim());
c = new IndustrialCustomer(customerAccountNum, customerName, "I");
c.ChargeAmount = c.CalculateCharge(kwhUsedPerCustomer, offpeakKwhUsedPerCustomer);
}
}
catch (ArgumentException excp)
{
MessageBox.Show($"Unable to create new customer, invalid information. {excp.Message}");
return;
}
catch (FormatException excp)
{
MessageBox.Show($"Non numeric data in a numeric field. {excp.Message}");
return;
}
//if a customer object is created successfully
// add the object to a customer list above and display in the list box
if (c != null)
{
CustomerList.Add(c);
customerListListBox.Items.Add(c.ToFormattedString());
}
//writing the customer data unto customer.txt!
try
{
string pathLocation = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
string fileLocation = Path.Combine(pathLocation, "Customer.txt");
StreamWriter output = new StreamWriter(fileLocation, true);
foreach (Customer customer in CustomerList)
{
output.WriteLine(customer.ToFileString());
}
output.Close();
}
catch (Exception excp)
{
MessageBox.Show($"File did not write. {excp.Message}");
return;
}
MessageBox.Show("Customer data has been save succesfully in customer.txt");
}