// When the form loads, initialize the fields on the the form and display the saved customer data.
private void frmElectricityCharges_Load(object sender, EventArgs e)
{
// Set the customer type to residential and put the focus on the usage input text box. The text
// fields will be null when the form first loads so this does not need to be done manually.
cboType.SelectedItem = "Residential";
lblUsage.Text = "Electricity Usage in kWh:";
txtUsage.Tag = "electricity usage";
lblUsagePeak.Visible = false;
txtUsagePeak.Visible = false;
txtUsage.Focus();
// Also read and display the data from the Customers.txt file, and display
// the associated calculations
custList = CustomerFile.ReadCustomers();
DisplayCustomerInfo();
}
// When the "Calculate and Add" button is clicked, obtain the user input (with validation) and
// execute the calculations to determine the customers's total charges. The new data is also
// added to the Customers.txt file, and displayed in the list box.
private void btnCalculate_Click(object sender, EventArgs e)
{
// Declare variables
bool success = false; // Indicates whether the calculation was successful
// Obtain the customer type from the combo box. cboType.DropDownStyle has been
// set to DropDownList, so the user cannot type in anything, and the selection will
// always be either residential, commercial or industrial, and there is no need for
// a default case.
// In all cases, verify that input has been provided for all fields (customer name, account,
// and usage(s)). Verify that the account number is a positive integer, and that the usage
// field(s) are non-negative integers.
switch (cboType.SelectedItem.ToString())
{
case "Residential":
// Validate and obtain the user input
if (ValidateInput.IsProvided(txtName) &&
ValidateInput.IsProvided(txtAcctNum) &&
ValidateInput.IsPositiveInt(txtAcctNum) &&
ValidateInput.IsProvided(txtUsage) &&
ValidateInput.IsNonNegativeInt(txtUsage))
{
ResidentialCustomer rc = new ResidentialCustomer(Convert.ToInt32(txtAcctNum.Text),
txtName.Text);
rc.UsageKWH = Convert.ToInt32(txtUsage.Text);
rc.CalculateCharge();
lblCharges.Text = rc.ChargeAmount.ToString("c");
custList.Add(rc);
success = true;
}
break;
case "Commercial":
// Validate and obtain the user input
if (ValidateInput.IsProvided(txtName) &&
ValidateInput.IsProvided(txtAcctNum) &&
ValidateInput.IsPositiveInt(txtAcctNum) &&
ValidateInput.IsProvided(txtUsage) &&
ValidateInput.IsNonNegativeInt(txtUsage))
{
CommercialCustomer cc = new CommercialCustomer(Convert.ToInt32(txtAcctNum.Text),
txtName.Text);
cc.UsageKWH = Convert.ToInt32(txtUsage.Text);
cc.CalculateCharge();
lblCharges.Text = cc.ChargeAmount.ToString("c");
custList.Add(cc);
success = true;
}
break;
case "Industrial":
// Validate and obtain the user inputs (both off-peak and peak usages)
if (ValidateInput.IsProvided(txtName) &&
ValidateInput.IsProvided(txtAcctNum) &&
ValidateInput.IsPositiveInt(txtAcctNum) &&
ValidateInput.IsProvided(txtUsage) &&
ValidateInput.IsNonNegativeInt(txtUsage) &&
ValidateInput.IsProvided(txtUsagePeak) &&
ValidateInput.IsNonNegativeInt(txtUsagePeak))
{
IndustrialCustomer ic = new IndustrialCustomer(Convert.ToInt32(txtAcctNum.Text),
txtName.Text);
ic.UsageKWH = Convert.ToInt32(txtUsage.Text);
ic.UsagePeakKWH = Convert.ToInt32(txtUsagePeak.Text);
ic.CalculateCharge();
lblCharges.Text = ic.ChargeAmount.ToString("c");
custList.Add(ic);
success = true;
}
break;
}
// Re-display all of the customer data in the list box (the newly added customer
// information will now appear).
// No checking is done to determine whether the customer and/or account number already
// exist in the file; assume that multiple charges can appear in the file for the
// same customer/account.
if (success)
{
CustomerFile.WriteCustomers(custList);
DisplayCustomerInfo();
}
}
