Навигация по datagridview (данные с текстового файла)

Public Class Form4
    Private data()() As String
    Private k As Integer
    Private Sub Form4_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        DataGridView1.ColumnCount = 2
        DataGridView1.Columns(0).HeaderText = "Data1"
        DataGridView1.Columns(1).HeaderText = "Data2"
        DataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells
        k = 0
        Label1.Text = k
        Label2.Text = 0
    End Sub
    Private Sub Load_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim tmp() As String = IO.File.ReadAllLines("data.txt", System.Text.Encoding.Default)
        ReDim data(tmp.Length / 5 - 1)
        Dim j, i As Integer
        ReDim data(j)(3)
        For Each s As String In tmp
            If s = "-" Then
                j += 1
                i = 0
                ReDim data(j)(3)
                Continue For
            End If
            data(j)(i) = s
            i += 1
        Next
        Label1.Text = data.Length
    End Sub
    Private Sub First_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        k = 0
        showBlock(k)
    End Sub
    Private Sub End_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
        k = data.Length - 1
        showBlock(k)
    End Sub
    Private Sub Forward_Click(sender As System.Object, e As System.EventArgs) Handles Button4.Click
        k += 1
        If k = data.Length Then k = 0
        showBlock(k)
    End Sub
    Private Sub Backwards_Click(sender As System.Object, e As System.EventArgs) Handles Button5.Click
        k -= 1
        If k = -1 Then k = data.Length - 1
        showBlock(k)
    End Sub
    Private Sub showBlock(ByVal jj As Integer)
        DataGridView1.Rows.Clear()
        DataGridView1.RowCount = 4
        Dim ss() As String = data(jj)
        For i = 0 To ss.Length - 1
            Dim s() As String = Split(ss(i), "|")
            DataGridView1(0, i).Value = s(0)
            DataGridView1(1, i).Value = s(1)
        Next
        Label2.Text = jj + 1
    End Sub
End Class

Public Class Form4
    Private data()() As String
    Private k, blockLen As Integer
    Private Sub Form4_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        DataGridView1.ColumnCount = 2
        DataGridView1.Columns(0).HeaderText = "Data1"
        DataGridView1.Columns(1).HeaderText = "Data2"
        DataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells
        k = 0
        Label1.Text = k
        Label2.Text = 0
        blockLen = 6
        LoadData()
    End Sub
    Private Sub LoadData()
        Dim tmp() As String = IO.File.ReadAllLines("data2.txt", System.Text.Encoding.Default)
        ReDim data(tmp.Length / (blockLen + 1) - 1)
        Dim j, i As Integer
        ReDim data(j)(blockLen - 1)
        For Each s As String In tmp
            If s = "-" Then
                j += 1
                i = 0
                ReDim data(j)(blockLen - 1)
                Continue For
            End If
            data(j)(i) = s
            i += 1
        Next
        Label1.Text = data.Length
        showBlock(0)
    End Sub
    Private Sub First_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        k = 0
        showBlock(k)
    End Sub
    Private Sub End_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
        k = data.Length - 1
        showBlock(k)
    End Sub
    Private Sub Forward_Click(sender As System.Object, e As System.EventArgs) Handles Button4.Click
        k += 1
        If k = data.Length Then k = 0
        showBlock(k)
    End Sub
    Private Sub Backwards_Click(sender As System.Object, e As System.EventArgs) Handles Button5.Click
        k -= 1
        If k = -1 Then k = data.Length - 1
        showBlock(k)
    End Sub
    Private Sub showBlock(ByVal jj As Integer)
        DataGridView1.Rows.Clear()
        DataGridView1.RowCount = blockLen
        Dim ss() As String = data(jj)
        For i = 0 To ss.Length - 1
            Dim s() As String = Split(ss(i), "|")
            DataGridView1(0, i).Value = s(0)
            DataGridView1(1, i).Value = s(1)
        Next
        Label2.Text = jj + 1
    End Sub
End Class