With Option Strict On, I'm trying to do a simple loop that will calculate the factorial of a number sent from an input box. The calculated factorial should be displayed in a list box. This is my code so far and it does NOT work:

Dim factorialInput As String
Dim n As Double = Val(factorialInput)
Dim total As Double = 1
factorialInput = InputBox("Please enter an integer greater than or equal to zero.", "Provide a Value")


If n > 0 Then
For n = 1 To n
total = total * n
Next n
lstWorkbench.Items.Add(factorialInput & "! = " & total)
End If

If n < 0 Then
factorialInput = InputBox("Please enter an integer greater than or equal to zero.", "Provide a Value")
End If


The result from the code is blank.