'Author:  Eric Heim
'Class:   CS0004

Option Strict On
Option Explicit On

Public Class frmMain

    'Ok Button click event
    Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click
        'If the input for the score text box is not numeric then produce an error
        If Not IsNumeric(txtScore.Text) Then
            MessageBox.Show("The Score Must Be a Number", "The Score Must Be a Number")
        Else
            'Switch on the text in the score text box
            Select Case CDbl(txtScore.Text)
                Case 90 To 100
                    txtLetterGrade.Text = "A"
                Case 80 To 89
                    txtLetterGrade.Text = "B"
                Case 70 To 79
                    txtLetterGrade.Text = "C"
                Case 60 To 69
                    txtLetterGrade.Text = "D"
                Case 0 To 59
                    txtLetterGrade.Text = "F"
                Case Else
                    MessageBox.Show("Number Out of Valid Range", "Number Out of Valid Range")
            End Select
        End If
    End Sub
End Class