need help populating array

[jac130]

i need to populate an array with grades. there is an 'add students & grades' button. user is prompted by input box to enter a students name, then another input box to enter their grade. the student's name is displayed in a list box. but the grades need to be stored in an array. here is a portion of my code:

Public Class btnAdd
    Dim grades() As Double

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim name As String = InputBox("please enter a student's name.")
        'validate name
        Do While Not isvalidname(name)
            name = InputBox("please enter a student's name.")
        Loop
        'display info
        lstStudents.Items.Add(name)

        'validate grade
        Dim grade As String = InputBox("please enter a positive number for grades.")
        Do While Not IsPositiveNumber(grade)
            grade = InputBox("please enter a positive number for grades.")
        Loop
        'populate array
        Dim i As Integer
        For i = 0 To grades.GetUpperBound(0)
            grades(i) = Val(grade)
        Next
    End Sub

I'm stuck populating the array? any advice would be great. thanks.