VB Program not working, should be simple - vb.net

Question

This is a homework assignment, as far as I know I have everything I'm supposed to do. Yet it doesn't work for some reason. If I input "50000" for the Property Value, ".6" for the Assessment Percent, and ".7" for the Assessment Rate I should get "$210" for Property Tax, yet I keep getting only a zero, not sure what I missed. It's not due until Sunday, so if you only want to give me a hint that would also be appreciated. I've gone over the instructions and the code a few times and I'm still not seeing my mistake. I keep looking at "propertytaxLabel.Text = CDec(decTax)" like I messed up something there also.
Public Class Form1
Private Sub clearButton_Click(sender As Object, e As EventArgs) Handles clearButton.Click
valueTextBox.Clear()
percentTextBox.Clear()
rateTextBox.Clear()
propertytaxLabel.Text = ""
End Sub
Private Sub exitButton_Click(sender As Object, e As EventArgs) Handles exitButton.Click
Me.Close()
End Sub
Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
Dim result As DialogResult
result = MessageBox.Show("Are you sure?", "Exit", MessageBoxButtons.YesNo)
If result = DialogResult.No Then
e.Cancel = True
End If
End Sub
Private Sub calculateButton_Click(sender As Object, e As EventArgs) Handles calculateButton.Click
Try
Dim decValue, decPercent, decRate, decTax As Decimal
decValue = CDec(valueTextBox.Text)
decPercent = CDec(percentTextBox.Text)
decRate = CDec(rateTextBox.Text)
propertytaxLabel.Text = CStr(decTax)
If proceduresRadioButton.Checked = True Then
TaxCalcProc(decValue, decPercent, decRate, decTax)
Else
decTax = TaxCalcFunc(decValue, decPercent, decRate)
End If
FormatCurrency(decTax)
Catch ex As Exception
MessageBox.Show("Error: Did you enter the data correctly?")
End Try
End Sub
Private Sub TaxCalcProc(ByVal propVal As Decimal, ByVal perc As Decimal, ByVal rate As Decimal, ByRef tax As Decimal)
Dim AssessedValue As Decimal
Try
AssessedValue = propVal * perc
tax = AssessedValue / 100 * rate
If rate > 1 Or perc > 1 Then
Throw New Exception("Tax Greater Than Value. Did you use the decimal point?")
End If
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub
Private Function TaxCalcFunc(ByVal propVal As Decimal, ByVal perc As Decimal, ByVal rate As Decimal) As Decimal
Dim tax As Decimal
Dim AssessedValue As Decimal
Try
AssessedValue = propVal * perc
tax = AssessedValue / 100 * rate
If rate > 1 Or perc > 1 Then
Throw New Exception("Tax Greater Than Value. Did you use the decimal point?")
End If
Catch ex As Exception
MessageBox.Show(ex.Message)
Return 0
End Try
Return Tax
End Function
End Class

Answer 1

You are printing out your decTax to your label after you are declaring it, but not after you are calculating it.
Try moving propertytaxLabel.Text = CStr(decTax) to after FormatCurrency(decTax) inside your button click event.

Answer 2

My VB is rusty, but you're not by any chance trying to convert "50,000" to a number, and it's failing because it has a comma in it? Most string -> int and string -> float conversions (in other languages) don't like commas.

Answer 3

First, you should research debugging and setting breakpoints with Visual Studio. It would make solving this very easy. Barring that, you can isolate and test your function with the following:
Private Sub calculateButton_Click(sender As Object, e As EventArgs) Handles calculateButton.Click
Dim decTax As Decimal
TaxCalcProc(50000D, 0.6D, 0.7D, decTax)
Dim resultString = Format(decTax, "C")
MessageBox.Show("decTax = " + resultString, "Test", MessageBoxButtons.Ok)
End Sub
Also, change:
AssessedValue / 100 * rate
to:
AssessedValue / 100D * rate
You probably have an unintentional case to Int because of the divide by 100. 100D tells the compiler that you want a decimal number.