reconbobber reconbobber - 1 month ago 7
Vb.net Question

How to I make the values in the list box round to two decimal places with this visual basic code

I have written this code in visual basic to solve a basic interest calculation. The year end balances are shown in the list box and the final total is show in the label. My problem is that I can not figure out how to round the values in the list box to two decimals. I have tried various things but with no luck so far so I appreciate any help.

Public Class frmNestEgg
Private Sub btnPrincipal_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click
' Declare and Initialize the variables

Dim Principal As Double = txtPrincipal.Text
Dim InterestRate As Double = txtInterestRate.Text / 100
Dim Years As Integer
Dim FinalTotal As Double
Dim YrEndAmt As Double

Years = Integer.Parse(txtYears.Text)

'Calculate the interest from the principal payment over the years input to create a total value.
For Years = 1 To Years
FinalTotal = Principal * Math.Pow((1 + InterestRate), Years)
YrEndAmt = (FinalTotal - Principal) + Principal
lstYrEndAmt.Items.Add("Year" & Years & " Balance " & YrEndAmt)
lblFinalTotal.Visible = True
lblFinalTotal.Text = FinalTotal.ToString("f1")
Next


End Sub

Private Sub frmNestEgg_Load(sender As Object, e As EventArgs) Handles MyBase.Load

End Sub


End Class

Answer

you could use

Math.Round() 
... & Math.Round(YrEndAmt, 2).ToString()

but your code had a flaw: same variable Years for looping and end condition

so change:

    For Years = 1 To Years

to:

    Dim Years As Integer, year As Integer

    For year = 1 To Years

your entire code would then be:

Private Sub btnPrincipal_Click(sender As Object, e As EventArgs) Handles btnPrincipal.Click
    Dim Principal As Double = txtPrincipal.Text
    Dim InterestRate As Double = txtInterestRate.Text / 100
    Dim Years As Integer, year As Integer
    Dim FinalTotal As Double
    Dim YrEndAmt As Double

    Years = Integer.Parse(txtYears.Text)

    'Calculate the interest from the principal payment over the years input to create a total value.
    For year = 1 To Years
        FinalTotal = Principal * Math.Pow((1 + InterestRate), Years)
        YrEndAmt = (FinalTotal - Principal) + Principal
        lstYrEndAmt.Items.Add("Year" & year & " Balance " & Math.Round(YrEndAmt, 2).ToString())
        lblFinalTotal.Visible = True
        lblFinalTotal.Text = FinalTotal.ToString("f1")
    Next
End Sub