如何在vbnet上随机化测验

Question

I'm new at visual basic programming and everything was fine until our topic shifted to arrays. I tried to understand it's code using Java. (Example: method are called functions.. .)

My prof has given us an exercise to create a Quiz program that asks the user more than 5 questions (in textbox) with choices (in buttons) and computes the score at the end (All just in one form). If the user click an a button it will tell if it's right or wrong and then proceed to change the question along with the choices.

*Required: - After the user finish the quiz the score will be displayed and there should be a restart button and all the question will be asked again randomly no pattern. - Try to make functions.

I tried searching the web since yesterday and I still have made no progress at my code.

Public Class Form1
    Dim questions(5) As String
    Dim answers(5) As String

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Method/Function for loading the Q&A
        loadQsAndAs()
    End Sub
    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        Me.Close()
    End Sub

    Private Sub loadQsAndAs()
        'Questions
        questions(0) = "What is 1 + 1?"
        questions(1) = "Who is the first man to walk on the Moon?"
        questions(2) = "What is the name of the main character in the movie: Yes Man! (2007)"
        questions(3) = "If I gave you three apples and you ate two, how many is left?"
        questions(4) = "What do you want in your final grade?"
        questions(5) = "What is the name of the thing(s) that you use whenever you eat?"
        'Answers
        answers(0) = "2"
        answers(1) = "Neil Armstrong"
        answers(2) = "Jim Carrey"
        answers(3) = "1"
        answers(4) = "A 4.0"
        answers(5) = "A Spoon and Fork"

        TextBox1.Text = setTheQuestion()
        Button1.Text = setTheAnswer1()
        Button2.Text = setTheAnswer2()
        Button3.Text = setTheAnswer3()
        Button4.Text = setTheAnswer4()

    End Sub

    Private Function setTheQuestion() As String
        Dim randomValue As New Random
        Dim randomQ As String = ""
        Dim i As Integer
        Dim index As Integer

        For i = 0 To 0
            index = randomValue.Next(0, questions.Length)
            randomQ &= questions(index)
        Next
        Return randomQ
    End Function

    Private Function setTheAnswer1() As String
        Dim randomValue As New Random
        Dim randomAns As String = ""
        Dim i As Integer
        Dim index As Integer

        For i = 0 To 0
            index = randomValue.Next(0, answers.Length)
            randomAns &= answers(index)
        Next

        Return randomAns
    End Function

    Private Function setTheAnswer2() As String
        Dim randomValue As New Random
        Dim randomAns As String = ""
        Dim i As Integer
        Dim index As Integer

        For i = 0 To 0
            index = randomValue.Next(1, answers.Length)
            randomAns &= answers(index)
        Next

        Return randomAns
    End Function

    Private Function setTheAnswer3() As String
        Dim randomValue As New Random
        Dim randomAns As String = ""
        Dim i As Integer
        Dim index As Integer
        For i = 0 To 0
            index = randomValue.Next(2, answers.Length)
            randomAns &= answers(index)
        Next

        Return randomAns
    End Function

    Private Function setTheAnswer4() As String
        Dim randomValue As New Random
        Dim randomAns As String = ""
        Dim i As Integer
        Dim index As Integer

        For i = 0 To 0
            index = randomValue.Next(3, answers.Length)
            randomAns &= answers(index)
        Next

        Return randomAns
    End Function

    Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As  System.EventArgs) Handles Button6.Click
        loadQsAndAs()
    End Sub
End Class

Answer 1

Public Class Form1
Dim questions As New ArrayList
Dim answers As New ArrayList
Dim dtQAMain As New DataTable
Dim questionsCopy As New ArrayList
Dim alAnsButton As New ArrayList 'arraylist to store all answer button.
Dim totalScore As Integer


Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) 
Handles MyBase.Load
    'Method/Function for loading the Q&A
    alAnsButton.Add(Button1)
    alAnsButton.Add(Button2)
    alAnsButton.Add(Button3)
    alAnsButton.Add(Button4)

    loaddtQA()
    loadQsAndAs()
End Sub

Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) 
Handles Button5.Click
    Me.Close()
End Sub

Private Sub loaddtQA()
    dtQAMain = New DataTable
    dtQAMain.Columns.Add("Q")
    dtQAMain.Columns.Add("A")

    For i = 0 To 5
        questions.Add("")
        answers.Add("")
    Next

    'Questions
    questions(0) = "What is 1 + 1?"
    questions(1) = "Who is the first man to walk on the Moon?"
    questions(2) = "What is the name of the main character in the movie: Yes Man!(2007)"
    questions(3) = "If I gave you three apples and you ate two, how many is left?"
    questions(4) = "What do you want in your final grade?"
    questions(5) = "What is the name of the thing(s) that you use whenever you eat?"
    'Answers
    answers(0) = "2"
    answers(1) = "Neil Armstrong"
    answers(2) = "Jim Carrey"
    answers(3) = "1"
    answers(4) = "A 4.0"
    answers(5) = "A Spoon and Fork"

    For i = 0 To questions.Count - 1
        dtQAMain.Rows.Add(questions(i), answers(i)) 'assign QA in table for scoring purpose later
    Next
End Sub
Private Sub loadQsAndAs()
    Label1.Visible = False
    For i = 0 To alAnsButton.Count - 1
        alAnsButton(i).visible = True
    Next
    questionsCopy = New ArrayList
    questionsCopy = questions.Clone 'close a copy so we dont effect the actual question copy when randomize and eliminate asked question from arraylist
    TextBox1.Text = setTheQuestion()
    setTheAnswer()
End Sub

Private Function setTheQuestion() As String

    Dim randomValue As New Random
    Dim randomQ As String = ""
    Dim index As Integer
    If questionsCopy.Count <> 0 Then
        index = randomValue.Next(0, questionsCopy.Count - 1)
        randomQ = questionsCopy(index)
        questionsCopy.RemoveAt(index) 'asked question will be remove.

    Else ' questions are finished, show the mark
        ShowMark()
    End If

    Return randomQ

End Function

Private Sub setTheAnswer() 'randonmize the answer and assign to button

    If TextBox1.Text = "" Then Exit Sub ' if question finish exit sub
    Dim randomValue As New Random
    Dim NewIndex As Integer
    Dim temp As String
    Dim answersCopy As ArrayList = answers.Clone
    For n = answersCopy.Count - 1 To 0 Step -1
        NewIndex = randomValue.Next(0, n + 1)
        ' Swap them.
        temp = answersCopy(n)
        answersCopy(n) = answersCopy(NewIndex)
        answersCopy(NewIndex) = temp
    Next

    Dim AnswerRowCheck As Integer = questions.IndexOf(TextBox1.Text)
    Dim ActualAnswer As String = dtQAMain.Rows(AnswerRowCheck).Item("A") 'check actual answer
    Dim totalRemove As Integer = 0
    For i = answersCopy.Count - 1 To 0 Step -1
        If totalRemove = 2 Then Exit For
        If answersCopy(i) <> dtQAMain.Rows(AnswerRowCheck).Item("A") Then
            answersCopy.RemoveAt(i)
            totalRemove += 1
        End If
    Next 'remove 2 of the selection,since only 4 button for answer selection and should not take out the actual answer


    For i = 0 To alAnsButton.Count - 1
        alAnsButton(i).text = answersCopy(i)
    Next

End Sub
Private Sub ShowMark()
    For i = 0 To alAnsButton.Count - 1
        alAnsButton(i).text = "" 'clear the text, no more input receive from user.
    Next
    Label1.Visible = True
    Label1.Text = totalScore & " out of 6 are correct."
End Sub

Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
    totalScore = 0
    loadQsAndAs() 'refresh question
End Sub

Private Sub Button4_MouseClick(sender As Object, e As MouseEventArgs) Handles Button4.MouseClick, Button3.MouseClick, Button2.MouseClick, Button1.MouseClick
    If sender.text = "" Then Exit Sub
    Dim AnswerRowCheck As Integer = questions.IndexOf(TextBox1.Text) 'search question number 
    If dtQAMain.Rows(AnswerRowCheck).Item("A") = sender.text Then 'checking answer 
        totalScore += 1
    End If
    TextBox1.Text = setTheQuestion() 'next question
    setTheAnswer()
End Sub
End Class

The code had cover most of the necessary comment which include the idea and how it work. Random() and arraylist are the key for this program to function, just pay more attention on it. Good luck.

Answer 2

How about trying this?

Public Class Form1

    Dim questions(5) As String
    Dim answers(5) As String

    Private Sub loadQsAndAs()
        'Questions
        questions(0) = "What is 1 + 1?"
        questions(1) = "Who is the first man to walk on the Moon?"
        questions(2) = "What is the name of the main character in the movie: Yes Man! (2007)"
        questions(3) = "If I gave you three apples and you ate two, how many is left?"
        questions(4) = "What do you want in your final grade?"
        questions(5) = "What is the name of the thing(s) that you use whenever you eat?"
        'Answers
        answers(0) = "2"
        answers(1) = "Neil Armstrong"
        answers(2) = "Jim Carrey"
        answers(3) = "1"
        answers(4) = "A 4.0"
        answers(5) = "A Spoon and Fork"

        Dim random As New Random
        Dim indices = { 0, 1, 2, 3, 4, 5 }.OrderBy(Function (n) random.Next()).ToArray()
        Dim question = random.Next(questions.Length - 1)

        TextBox1.Text = questions(indices(question))

        Button1.Text = answers(indices(0))
        Button2.Text = answers(indices(1))
        Button3.Text = answers(indices(2))
        Button4.Text = answers(indices(3))

    End Sub

End Class

That's it. Nice and simple. The key trick is creating a randomize indices array to do the lookups into the questions and answers arrays.

Answer 3

Private Dim rnd As Integer

Private Function setTheQuestion() As String
    rnd = (CInt(Math.Ceiling(Rnd() * questions.Length)) + 1)
    Return questions(rnd)
End Function

Private Function setTheAnswer1() As String
    Return answers(rnd)
End Function