Description

We are learning to create computer applications using the Visual Basic language. This is one of our intrpductory lessons to desktop applications. In exercise, we will use Microsoft Visual Studio to create a project. We will create a Windows Forms application, also called WinForms app.

One of the strengths of the Visual Basic language is that it has its own library that provides many functions you can directly use in your applications. One of the categories of functions deals with investments calculations. This means that the Visual Basic language provides functions that allow you to calculate the present value of an investments, the future value, the interest rate, etc. In this exercise, we will calculate the future value and the interest earned on an investment.

Practical Learning: Creating the Application

1. Start Microsoft Visual Studio
2. On the Visual Studio 2026 dialog box, click Create a New Project
3. In the Create a New Project dialog box, in the Languages combo box, select Visual Basic
4. In the list project templates, click Windows Forms App
5. Click Next
6. In the Configure Your New Project dialog box, set the Project Name to AnnuityEvaluation
7. Click Next
8. In the Additional Information dialog box, in the Framework combo box, select the highest version (.NET 10.0 (Long Term Support)).
   Click Create
9. In the Solution Explorer, right-click Form1.cs and click Rename
10. Type Exercise (to get Exercise.cs) and press Enter twice
11. Click the body of the form to select it
12. In the Properties window, change the following characteristics:

    Text:          Annuity Evaluation
    StartPosition: CenterScreen
    MaximizeBox:   False

13. Design the form as followed:

    

    Control		Name	Text	Additional Properties
    GroupBox			Annuity Preparation
    Label			Present Value:
    TextBox		TxtPresentValue		TextAlign: Right
    Label			Interest Rate:
    TextBox		TxtInterestRate		TextAlign: Right
    Label			%
    Label			Number of Payments:
    TextBox		TxtNumberOfPayments		TextAlign: Text
    Label			Months
    Label			Periodic Payment:
    TextBox		TxtPeriodicPayment		TextAlign: Right
    Label			Payment Made At:
    ComboBox		CbxDueDates		Items: End of Period Beginning of Period
    Button		btnEvaluate	Evaluate
    GroupBox			Annuity Results
    Label			Future Value:
    TextBox		TxtFutureValue		TextAlign: Right
    Button		btnClose	Close

14. On the form, double-click the Calculate button and implement its Click() event as follows:
    

    Private Sub BtnEvaluate_Click(sender As Object, e As EventArgs) Handles BtnEvaluate.Click
        Dim DateDue As DueDate
        Dim PresentValue As Double
        Dim TotalPayments As Integer
        Dim InterestRate As Double
        Dim PeriodicPayment As Double
    
        PresentValue = CDbl(TxtPresentValue.Text)
        InterestRate = CDbl(TxtInterestRate.Text) / 100
        TotalPayments = CInt(TxtNumberOfPayments.Text)
        PeriodicPayment = CDbl(TxtPeriodicPayment.Text)
    
    
        DateDue = IIf(CbxDueDates.SelectedIndex = 0, DueDate.EndOfPeriod, DueDate.BegOfPeriod)
    
        Dim FutureValue As Double = FV(InterestRate / 12, TotalPayments, -PeriodicPayment, 0, DateDue)
    
        TxtFutureValue.Text = FormatNumber(FutureValue)
    End Sub

15. Return to the form and double-click the Close button
16. Implement its OnClick() event as follows:

    Private Sub BtnClose_Click(sender As Object, e As EventArgs) Handles BtnClose.Click
        Close()
    End Sub

17. To test the application, press Ctrl + F5

    

18. In the top text boxes, specify the values as follows:

    Present Value:      100
    Interest Rate:      2.725
    Number of Payments: 60
    Periodic Payment:   150
    Payment Made At:    Beginning of Period

19. Click the Evaluate button:

    

20. Close the form and return to your programming environment
21. Close your programming environment

Application

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