Error on inserting new line on gridview - vb.net

Question

I am trying to add a new row into a gridview but for some reason i'm having a problem in the for loop.
Directly goes to dtCurrentTable.Rows.Add(drCurrentRow) and of course, have an error "'row' argument cannot be null.Parameter name: row", because the dtcurrentTable.NewRow was not executed.
Why is this happening?
Private Sub AddNewRowToGrid()
Dim rowIndex As Integer = 0
If Not IsNothing(ViewState("CurrentTable")) Then
Dim dtCurrentTable As DataTable = CType(ViewState("CurrentTable"), DataTable)
Dim drCurrentRow As DataRow = Nothing
If dtCurrentTable.Rows.Count > 0 Then
For i as Integer = 1 To i <= dtCurrentTable.Rows.Count
' Extraem-se os valores das Textbox
Dim box1 As TextBox = Dados.Rows(rowIndex).Cells(0).FindControl("Artigo")
Dim box2 As TextBox = Dados.Rows(rowIndex).Cells(1).FindControl("Descricao")
Dim box3 As TextBox = Dados.Rows(rowIndex).Cells(2).FindControl("IVA")
Dim box4 As TextBox = Dados.Rows(rowIndex).Cells(3).FindControl("PU")
Dim box5 As TextBox = Dados.Rows(rowIndex).Cells(4).FindControl("Desconto")
Dim box6 As TextBox = Dados.Rows(rowIndex).Cells(5).FindControl("UN")
Dim box7 As TextBox = Dados.Rows(rowIndex).Cells(6).FindControl("Quantidade")
Dim box8 As TextBox = Dados.Rows(rowIndex).Cells(7).FindControl("TotalLiquido")
drCurrentRow = dtCurrentTable.NewRow
dtCurrentTable.Rows(i - 1)("Artigo") = box1.Text
dtCurrentTable.Rows(i - 1)("Descricao") = box2.Text
dtCurrentTable.Rows(i - 1)("IVA") = box3.Text
dtCurrentTable.Rows(i - 1)("PU") = box4.Text
dtCurrentTable.Rows(i - 1)("Desconto") = box5.Text
dtCurrentTable.Rows(i - 1)("UN") = box6.Text
dtCurrentTable.Rows(i - 1)("Quantidade") = box7.Text
dtCurrentTable.Rows(i - 1)("TotalLiquido") = box8.Text
rowIndex += 1
Next i
dtCurrentTable.Rows.Add(drCurrentRow)
ViewState("CurrentTable") = dtCurrentTable
Dados.DataSource = dtCurrentTable
Dados.DataBind()
End If
Else
Response.Write("ViewState null")
End If
SetPreviousData()
End Sub

Answer 1

Your For loop is defined wrong, thats why you're getting an error:
For i as Integer = 1 To i <= dtCurrentTable.Rows.Count
evaluates to
For i as Integer = 1 To True
(because i is always <= Rows.Count)
which VB translates as
For i as Integer = 1 To -1
which means your loop never runs.
It
should be
For i as Integer = 1 To dtCurrentTable.Rows.Count
Also, there's something odd about the way you use drCurrentRow = dtCurrentTable.NewRow. Why is that inside the loop when you don't do anything with it in the loop? It gets executed multiple times and then dtCurrentTable.Rows.Add(drCurrentRow) only gets called once.
Its hard for me to correct because I can't figure out what you're trying to do, but that bit looks dodgy to me.