How to debug a cast execption in vb.net? - vb.net

Question

I am getting a cast exception and I have re-written this code a large number of times. I am getting the exception on the following line:
If (CInt(hHurricaneYear) < CInt(_strYears(hAverage))) Then
And I am only getting results in the lblNumberOfHurricans. the other two labels are not showing any results. I thought I was getting it when the cast exception showed up.
Can anyone suggest how to get the results and stop the exception?
Here is what I have so far (well at least the last try).
Option Strict On
Public Class frmHurricaneStatistics
' Class level Private variables.
Public Shared _intSizeOfArray As Integer = 20
Private _strYears(_intSizeOfArray) As String
Private _intNumberOfHurricans(_intSizeOfArray) As Integer
Private Sub frmHurricaneStatistics_Load(sender As Object, e As EventArgs
) Handles MyBase.Load
' This load event reads the inventory text file and fills
' the ComboBox object with the Hurricane Statistics.
' Initialize an instace of the streamreader object and declare variables.
Dim objReader As IO.StreamReader
Dim strHurricaneStatistics As String = "Hurricanes.txt"
Dim intCount As Integer = 0
Dim intFill As Integer
Dim strFileError As String = "The file is not available. Please restart the
application when the file is available."
' Verify the Hurricane.txt file exists.
If IO.File.Exists(strHurricaneStatistics) Then
objReader = IO.File.OpenText(strHurricaneStatistics)
' Read the file line by line until the file is completed.
Do While objReader.Peek <> -1
_strYears(intCount) = objReader.ReadLine()
_intNumberOfHurricans(intCount) = Convert.ToInt32(objReader.ReadLine())
intCount += 1
Loop
objReader.Close()
' The ComboBox objext is filled with the Years for Hurricanes.
For intFill = 0 To (_strYears.Length - 1)
cmbYears.Items.Add(_strYears(intFill))
Next
Else
MsgBox(strFileError, , "Error")
Close()
' If ComboBox is filled then enable the Display Statistics button.
'btnDisplayStatistics.Enabled = True
End If
End Sub
Private Sub btnDisplayStatistics_Click(sender As Object, e As EventArgs
) Handles btnDisplayStatistics.Click
' This click event calls the sub procedures for the selected years and
' the number of hurricans in that year.
Dim intSelectedYear As Integer
Dim strMissingSelection As String = "Missing Selection"
Dim strSelectAYearError As String = "Please Select a Year"
' If the ComboBox object has a selection, Display Statistics.
If cmbYears.SelectedIndex >= 0 Then
intSelectedYear = cmbYears.SelectedIndex
Else
MsgBox(strSelectAYearError, , strMissingSelection)
End If
Private Sub btnDisplayStatistics_Click(sender As Object, e As EventArgs
) Handles btnDisplayStatistics.Click
' This click event calls the sub procedures for the selected years and
' the number of hurricans in that year.
Dim intSelectedYear As Integer
Dim strMissingSelection As String = "Missing Selection"
Dim strSelectAYearError As String = "Please Select a Year"
' If the ComboBox object has a selection, call the Display Statistics procedure.
If cmbYears.SelectedIndex >= 0 Then
intSelectedYear = cmbYears.SelectedIndex
Else
MsgBox(strSelectAYearError, , strMissingSelection)
End If
' This procedure MakeLabelsVisible Is called to display the labels
' And the results.
MakeLabelsVisible()
Dim hHurricaneAverage As Integer
Dim hHurricaneYear As Integer = 0
For hAverage As Integer = 0 To _strYears.Length - 1
If (CInt(hHurricaneYear) < CInt(_strYears(hAverage))) Then
hHurricaneYear = CInt(CType(CInt(_strYears(hAverage)), String))
End If
hHurricaneAverage = hHurricaneAverage + CInt((_strYears.ToString))
hHurricaneAverage = CInt(hHurricaneAverage / _strYears.Length)
Next
' Display the statistics for the Storm Average in the selected Year
' and the most active year within the range of year.
lblNumberOfHurricanes.Text = "The Number of Hurricanes in the Year " &
_strYears(intSelectedYear) & " is " & _intNumberOfHurricans(intSelectedYear).ToString() & "."
lblAvergeNumberHurricanes.Text = "The Average Number of Storms was " &
hHurricaneAverage & " Hurricanes."
Dim intSizeOfArray As Integer = Nothing
lblMostStorms.Text = "The Year "(CInt(_strYears(CInt(hHurricaneYear.ToString())) & "
Had The Most Storms Between " & (_strYears(0) & _strYears(20).ToString)))
End Sub
Option strict on

Answer 1

Your error lies in that you are trying to convert an entire string array into an integer:
hHurricaneAverage = hHurricaneAverage + CInt((_strYears.ToString))
You will need to call the index of _strYears:
hHurricaneAverage = hHurricaneAverage + CInt((_strYears(hAverage).ToString))
This will also explain why the other labels do not update, because hHurricanAverage never gets calculated.