Must be in Visual Basic code

Extra 8-1 Display a test scores array

In this exercise, youll enhance the Score Calculator form of extra exercise 4-2 so it saves the scores the user enters in an array and then lets the user display the sorted scores in a dialog box

Open the ScoreCalculator project in the Extra Exercises\Chapter 08\ScoreCalculator With Array directory. This is the Score Calculator form from extra exercise 4-2 with data validation and exception handling added.

Declare a module-level variable for an array that can hold up to 20 scores.

Modify the Click event handler for the Add button so it adds the score thats entered by the user to the next element in the array. To do that, you can use the score count variable to refer to the element.

Move the Clear Scores button as shown above. Then, modify the Click event handler for this button so it removes any scores that have been added to the array. The easiest way to do that is to create a new array and assign it to the array variable.

Add a Display Scores button that sorts the scores in the array, displays the scores in a dialog box, and moves the focus to the Score text box. Be sure that only the elements that contain scores are displayed.

Test the application to be sure it works correctly.

This is what I have to start with:

Public Class Form1

Dim total As Integer = 0

Dim count As Integer = 0

Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click

Try

If IsValidData() Then

Dim score As Integer = CInt(txtScore.Text)

total += score

count += 1

Dim average As Integer = CInt(Math.Round(total / count, 0, MidpointRounding.AwayFromZero))

txtScoreTotal.Text = total.ToString

txtScoreCount.Text = count.ToString

txtAverage.Text = average.ToString

txtScore.Select()

End If

Catch ex As Exception

MessageBox.Show(ex.Message & vbCrLf & vbCrLf &

ex.GetType().ToString & vbCrLf &

ex.StackTrace, "Exception")

End Try

End Sub

Public Function IsValidData() As Boolean

Return _

IsPresent(txtScore, "Score") AndAlso

IsInt32(txtScore, "Score") AndAlso

IsWithinRange(txtScore, "Score", 1, 100)

End Function

Public Function IsPresent(textbox As TextBox, name As String) _

As Boolean

If textbox.Text = "" Then

MessageBox.Show(name & " is a required field.", "Entry Error")

textbox.Select()

Return False

Else

Return True

End If

End Function

Public Function IsInt32(textbox As TextBox, name As String) _

As Boolean

Dim number As Integer = 0

If Int32.TryParse(textBox.Text, number) Then

Return True

Else

MessageBox.Show(name & " must be an integer.", "Entry Error")

textbox.Select()

textbox.SelectAll()

Return False

End If

End Function

Public Function IsWithinRange(textbox As TextBox, name As String,

min As Decimal, max As Decimal) As Boolean

Dim number As Decimal = CDec(textbox.Text)

If number < min OrElse number > max Then

MessageBox.Show(name & " must be between " & min & " and " &

max & ".", "Entry Error")

textbox.Select()

textbox.SelectAll()

Return False

Else

Return True

End If

End Function

Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click

total = 0

count = 0

txtScore.Text = ""

txtScoreTotal.Text = ""

txtScoreCount.Text = ""

txtAverage.Text = ""

txtScore.Select()

End Sub

Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click

Me.Close()

End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

End Sub

End Class