How to modify a value in the array in visual basic - arrays

Question

The following is the code which I am using for creating a two dimensional array
Public Class frmGrades
Private Score As Dictionary(Of String, String) = New Dictionary(Of String, String)
Private Sub cmdApply_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdApply.Click
Static intNumber As Integer
ReDim Preserve Score(1, intNumber)
Score(0, intNumber) = txtStudent.Text
Score(1, intNumber) = txtGrade.Text
hsbStudent.Maximum = intNumber
hsbStudent.Value = intNumber
intNumber = intNumber + 1
txtGrade.Clear()
txtStudent.Clear()
txtStudent.Focus()
End Sub
Private Sub hsbStudent_Scroll(ByVal sender As Object, ByVal e As System.Windows.Forms.ScrollEventArgs) Handles hsbStudent.Scroll
txtStudent.Text = Score(0, hsbStudent.Value)
txtGrade.Text = Score(1, hsbStudent.Value)
End Sub
Private Sub cmdFirst_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdFirst.Click
txtStudent.Text = Score(0, hsbStudent.Minimum)
txtGrade.Text = Score(1, hsbStudent.Minimum)
End Sub
Private Sub cmdLast_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdLast.Click
txtStudent.Text = Score(0, hsbStudent.Maximum)
txtGrade.Text = Score(1, hsbStudent.Maximum)
End Sub
**Private Sub CmdEdit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CmdEdit.Click
If Score.ContainsKey(txtStudent.Text) Then
Score.Item(txtStudent.Text) = txtGrade.Text
Else
Score.Add(txtStudent.Text, txtGrade.Text)
End If
End Sub
End Class**
Now I would like to edit the grade text box which should also change the grade in the array. Any idea on how could this be done.

Answer 1

UPDATE:
OK, I see the code has a little more now and the problem is more clear as well as the need for a different approach. I rewrote your code. See if this works for you:
Public Class frmGrades
Public Class StudentGrade
Public Name As String
Public Grade As String
End Class
Private Score As List(Of StudentGrade) = New List(Of StudentGrade)
Private Sub cmdApply_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdApply.Click
AddStudent()
End Sub
Private Sub hsbStudent_Scroll(ByVal sender As Object, ByVal e As System.Windows.Forms.ScrollEventArgs) Handles hsbStudent.Scroll
Update(hsbStudent.Value - 1) 'lists are zero-based
End Sub
Private Sub cmdFirst_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdFirst.Click
Update(0)
End Sub
Private Sub cmdLast_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdLast.Click
Update(hsbStudent.Maximum - 1)
End Sub
Private Sub AddStudent()
Dim nm As New StudentGrade
nm.Name = txtStudent.Text
nm.Grade = txtGrade.Text
Score.Add(nm)
hsbStudent.Minimum = 1
hsbStudent.Maximum = Score.Count
hsbStudent.Value = Score.Count
txtGrade.Clear()
txtStudent.Clear()
txtStudent.Focus()
End Sub
Private Sub Update(i As Integer)
txtStudent.Text = Score(i).Name
txtGrade.Text = Score(i).Grade
End Sub
Private Sub CmdEdit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CmdEdit.Click
Dim index As Integer = -1, cnt As Integer = 0
For Each nm As StudentGrade In Score
If nm.Name.ToLower = txtStudent.Text.ToLower Then
index = cnt
Exit For
End If
cnt += 1
Next
If index = -1 Then
AddStudent()
Else
Score(index).Name = txtStudent.Text
Score(index).Grade = txtGrade.Text
hsbStudent.Value = index + 1
End If
End Sub
End Class
With this code you can expand the class StudentGrade to contain whatever you need to store. The list, contrary to dictionary, allow you to use index values as well.