How to loop if userAnswer = correctAnswer

See more:

VB

Hi,

I'm having trouble with the Try...Catch code. I'm trying to make the textboxes only accept letters A, B, C, or D as answers from the user. I'm also having trouble matching the two arrays. I wanted it to be like if textbox1 is A then it is correct but in a loop. Please take a look at my code. Any help is appreciated. Thank you.

This is the programming challenge instruction for reference:
The local Registry of Motor Vehicles office has asked you to create an application that grades the written portion of the driver's license exam. The exam has 20 multiple choice questions. Here are the correct answers to the questions:
1. B 6. A 11. B 16. C
2. D 7. B 12. C 17. C
3. A 8. A 13. D 18. B
4. A 9. C 14. A 19. D
5. C 10.D 15. D 20. A

Public Class frmJPDLExamm
    Dim intMinutes As Integer   'Holds the minutes for the timer
    Private Sub btnScore_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnScore.Click
        Dim AnswersForm As New frmAnswers
        'Correct answers as an array
        Dim achrCorrectAnswers() As Char = {"B", "D", "A", "A", "C", "A", "B", "A", "C", "D", "B", "C", "D", "A", "D", "C", "C", "B", "D", "A"}
        Dim intIncorrect As Integer     'Counter for incorrect answers
        Dim intCorrect As Integer       'Counter for correct answers
        Dim intCount As Integer         'Total counter
        Dim chrInput As Char            'Hold a char value
        Dim achrUserAnswers(19) As Char 'Textboxes as an array
        achrUserAnswers(0) = txt1.Text
        achrUserAnswers(1) = txt2.Text
        achrUserAnswers(2) = txt3.Text
        achrUserAnswers(3) = txt4.Text
        achrUserAnswers(4) = txt5.Text
        achrUserAnswers(5) = txt6.Text
        achrUserAnswers(6) = txt7.Text
        achrUserAnswers(7) = txt8.Text
        achrUserAnswers(8) = txt9.Text
        achrUserAnswers(9) = txt10.Text
        achrUserAnswers(10) = txt11.Text
        achrUserAnswers(11) = txt12.Text
        achrUserAnswers(12) = txt13.Text
        achrUserAnswers(13) = txt14.Text
        achrUserAnswers(14) = txt15.Text
        achrUserAnswers(15) = txt16.Text
        achrUserAnswers(16) = txt17.Text
        achrUserAnswers(17) = txt18.Text
        achrUserAnswers(18) = txt19.Text
        achrUserAnswers(19) = txt20.Text

        Try
            'Convert the user input from a textbox to a char
            strInput = CChar(achrUserAnswers(19))
            For intCount = 0 To 19
                'If the user's answer from the textbox is equals to the correct answer
                'from the corresponding array, then the answer is correct
                If achrUserAnswers(19) = achrCorrectAnswers(19) Then
                    intCorrect += 1
                    AnswersForm.lstAns.Items.Add("Correct")
                    'Else, the user's answer is incorrect
                Else
                    intIncorrect += 1
                    AnswersForm.lstAns.Items.Add("Incorrect")
                    intCount += 1
                End If
            Next
        Catch
            'Error message for invalid input
            MessageBox.Show("Enter letter A, B, C, or D only.")
        End Try

        'Display the total incorrect answers in the listbox
        AnswersForm.lstAns.Items.Add("You have a total of " & intIncorrect.ToString() & " Incorrect answers.")
        intCorrect = 20 - intIncorrect
        'Display the total correct answers in the listbox
        AnswersForm.lstAns.Items.Add("and a total of " & intCorrect.ToString() & " Correct answers.")

        'If the user has 15 or more correct answers, then the user pass the exam
        If intCorrect > 14 Then
            AnswersForm.lstAns.Items.Add("Congratulations! You have passed the Driver's License Exam.")
            'Else, the user fail the exam
        Else
            AnswersForm.lstAns.Items.Add("You have failed the Driver's License Exam. Try Again.")
        End If

        'Display the results in another form
        AnswersForm.ShowDialog()
    End Sub

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
        'Clears all textboxes. From textbox 1 to 20.
        txt1.Clear()
        txt2.Clear()
        txt3.Clear()
        txt4.Clear()
        txt5.Clear()
        txt6.Clear()
        txt7.Clear()
        txt8.Clear()
        txt9.Clear()
        txt10.Clear()
        txt11.Clear()
        txt12.Clear()
        txt13.Clear()
        txt14.Clear()
        txt15.Clear()
        txt16.Clear()
        txt17.Clear()
        txt18.Clear()
        txt19.Clear()
        txt20.Clear()
    End Sub

    Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
        'Close the form
        Me.Close()
    End Sub
    Private Sub btnToggle_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnToggle.Click
        'Toggle the timer
        If tmrMinutes.Enabled = True Then
            tmrMinutes.Enabled = False
            btnToggle.Text = "Start &Timer"
        Else
            tmrMinutes.Enabled = True
            btnToggle.Text = "Stop &Timer"
        End If
    End Sub

    Private Sub tmrMinutes_Tick_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrMinutes.Tick
        'Update the minutes display by one minute every minute
        intMinutes += 1
        lblCounter.Text = intMinutes.ToString()
    End Sub
End Class