0

Hey everyone i have some code here that bring in one line text from a file and displays into labels. I want to add up eight values from labels and divide by 8 to get the average, and convert that average score into a letter grade that will be displayed in a new label. The code i need help with is in the btnCal procedural.

Here is my code:

   Imports System.IO

   Public Class Form1
    Dim grade As String

    Private Sub ExitToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ExitToolStripMenuItem.Click
    Me.Close()

     End Sub

     Private Sub OpenToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles      OpenToolStripMenuItem.Click

    OFDG1.Filter = "Text Files|*.txt|All Files|*.*"
    Dim myResult As DialogResult
    myResult = OFDG1.ShowDialog
    If myResult = Windows.Forms.DialogResult.OK Then
        Dim strReader As StreamReader = File.OpenText(OFDG1.FileName)
        Dim aline As String
        Do Until strReader.EndOfStream
            aline = strReader.ReadLine
            Dim myStuff() = aline.Split(","c)
            lblStudent.Text = myStuff(0)
            lblClassField.Text = myStuff(1)
            lblSemesterInput.Text = myStuff(2)
            picStudent.Image = Image.FromFile(myStuff(3))
            lblInput1.Text = myStuff(4)
            lblInput2.Text = myStuff(5)
            lblInput3.Text = myStuff(6)
            lblInput4.Text = myStuff(7)
            lblInput5.Text = myStuff(8)
            lblInput6.Text = myStuff(9)
            lblMidtermInput.Text = myStuff(10)
            lblFinalInput.Text = myStuff(11)

        Loop
        strReader.Close()
    Else
        MessageBox.Show("You clicked other than OK")

    End If
End Sub

Private Sub btnCal_Click(sender As Object, e As EventArgs) Handles btnCal.Click

    grade = CStr(CInt(lblInput1.Text + lblInput2.Text + lblInput3.Text _
    + lblInput4.Text + lblInput5.Text + _
    lblInput6.Text + lblMidtermInput.Text + lblFinalInput.Text / 8)

    lblFinalLetterGrade.Text = Calculation(CInt(grade))

End Sub
Public Function Calculation(ByVal grade As Integer) As String
    Select Case grade
        Case Is > 89
            Return "A"
        Case Is > 79
            Return "B"
        Case Is > 69
            Return "C"
        Case Is > 59
            Return "D"
        Case Else
            Return "F"
    End Select
End Function
End Class
Ňɏssa Pøngjǣrdenlarp
  • 38,411
  • 12
  • 59
  • 178
king_sw4
  • 1,125
  • 2
  • 11
  • 18

1 Answers1

1

You are mixing up concatenation with addition (you can use + for both and, as far as you are not indicating the proper type (integer), VB.NET thinks that you mean strings and just concatenate them. In order to avoid this kind of errors, it is always better using & for concatenation and letting + just for addition) and not putting the proper brackets (division is considered before addition).

grade = CStr((CInt(lblInput1.Text) + CInt(lblInput2.Text) + CInt(lblInput3.Text) _
    + Cint(lblInput4.Text) + CInt(lblInput5.Text) + _
    CInt(lblInput6.Text) + CInt(lblMidtermInput.Text) + CInt(lblFinalInput.Text)) / 8)

In general, it seems like you should work a bit more on properly-structuring your code. Also you are using quite a few methods from old VB (e.g., CStr, CInt); some times there is no problem, other times might drive to confusing codes (e.g., .NET indexing starting always from 0 and certain old functions from 1). On the other hand, if you are programming in VB.NET, why are you using VB6 code at all?

varocarbas
  • 12,354
  • 4
  • 26
  • 37
  • Every project is complied with option strict on and option infer on... at least that is the way i have setup my machine – king_sw4 Nov 18 '13 at 17:27
  • @user2872778 Sorry, I corrected this bit. I misunderstood (as you did) that an addition among strings was performed (what is not allowed by Strict On); but actually, .NET assumes that you want to concatenate and thus does not trigger any error. Anyway... quite a few things to correct in this code. In any case, there you have the correction of grade (what you were looking for, I understand). – varocarbas Nov 18 '13 at 17:30
  • So i have to convert EVERY label when using string to a CInt for each label? – king_sw4 Nov 18 '13 at 17:33
  • @user2872778 not every label, EVERYTHING. You have always to perform the conversion to the proper type. Actually this is what Option Strict On is for: to force you to make always the conversion; this case (where + can be understood in two different ways) is pretty exceptional; most of the cases where you don't make the proper conversion are not allowed by Strict On. – varocarbas Nov 18 '13 at 17:35