Public Class frmInvoiceTotal Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click

'Dim subtotal As Decimal = CDec(txtSubtotal.Text)

Dim subtotal As Decimal = Decimal.Parse(txtSubtotal.Text)

Dim discountPercent As Decimal

If subtotal >= 500 Then discountPercent = 0.2D ElseIf subtotal >= 250 And Subtotal < 500 Then discountPercent = 0.15D ElseIf subtotal >= 100 And Subtotal < 250 Then discountPercent = 0.1D Else discountPercent = 0 End If

Dim discountAmount As Decimal = subtotal * discountPercent

Dim invoiceTotal As Decimal = subtotal - discountAmount

'txtDiscountPercent.Text = FormatPercent(discountPercent, 2)

txtDiscountAmount.Text = FormatCurrency(discountAmount, 2)

txtTotal.Text = FormatCurrency(invoiceTotal, 2)

txtDiscountPercent.Text = discountPercent.ToString("p2") txtDiscountAmount.Text = discountAmount.ToString("c2") txtTotal.Text = invoiceTotal.ToString("c2")

txtSubtotal.Select() End Sub

Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click Me.Close() End Sub End Class

In visual Studio, In this code,

Explain the CDec function,

Dim subtotal As Decimal = CDec(txtSubtotal.Text)

and

the Decimal Parse method

Dim subtotal As Decimal = Decimal.Parse(txtSubtotal.Text)

comment to explain the statement Discount Percent, discountAmount and invoicetotal format as following:

txtDiscountPercent.Text = FormatPercent(discountPercent, 2)

txtDiscountAmount.Text = FormatCurrency(discountAmount, 2)

txtTotal.Text = FormatCurrency(invoiceTotal, 2)

And comment to explain the ToString method for discountPercent, discountAmount and invoiceTotal.

txtDiscountPercent.Text = discountPercent.ToString("p2") txtDiscountAmount.Text = discountAmount.ToString("c2") txtTotal.Text = invoiceTotal.ToString("c2")

Explain those statements which are in this code. Do not give general statement, Stay in the code and explain it as a statement in this code Please.