Возможность обращаться к данным по ячейкам и изменять их

Public Class Form1
    Dim index As String
    Private Sub ЗагрузитьToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ЗагрузитьToolStripMenuItem.Click
        Dim fName As String = IO.Path.Combine(Application.StartupPath, "tst.txt")
        Dim records() As String = IO.File.ReadAllLines(fName, System.Text.Encoding.Default)
        Dim bb As New List(Of Biography)
        For Each rr As String In records
            bb.Add(New Biography(rr.Split(","c)))
        Next
        DataGridView1.DataSource = Nothing
        DataGridView1.DataSource = bb
    End Sub
 
    Private Sub МоскваToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles МоскваToolStripMenuItem.Click
        Dim fName As String = IO.Path.Combine(Application.StartupPath, "tst.txt")
        Dim records() As String = IO.File.ReadAllLines(fName, System.Text.Encoding.Default)
        Dim bb As New List(Of Biography)
        For Each rr As String In records
            bb.Add(New Biography(rr.Split(","c)))
        Next
        Dim sel = From b As Biography In bb Where b.Город = "Москва"
        DataGridView1.DataSource = Nothing
        If sel.Count > 0 Then
            DataGridView1.DataSource = sel.ToArray
        Else
            MsgBox("Нет данных!")
        End If
    End Sub
 
    Private Sub КалининградToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles КалининградToolStripMenuItem.Click
        Dim fName As String = IO.Path.Combine(Application.StartupPath, "tst.txt")
        Dim records() As String = IO.File.ReadAllLines(fName, System.Text.Encoding.Default)
        Dim bb As New List(Of Biography)
        For Each rr As String In records
            bb.Add(New Biography(rr.Split(","c)))
        Next
        Dim sel = From b As Biography In bb Where b.Город = "Калининград"
        DataGridView1.DataSource = Nothing
        If sel.Count > 0 Then
            DataGridView1.DataSource = sel.ToArray
        Else
            MsgBox("Нет данных!")
        End If
    End Sub
 
    Private Sub ТверьToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ТверьToolStripMenuItem.Click
        Dim fName As String = IO.Path.Combine(Application.StartupPath, "tst.txt")
        Dim records() As String = IO.File.ReadAllLines(fName, System.Text.Encoding.Default)
        Dim bb As New List(Of Biography)
        For Each rr As String In records
            bb.Add(New Biography(rr.Split(","c)))
        Next
        Dim sel = From b As Biography In bb Where b.Город = "Тверь"
        DataGridView1.DataSource = Nothing
        If sel.Count > 0 Then
            DataGridView1.DataSource = sel.ToArray
        Else
            MsgBox("Нет данных!")
        End If
    End Sub
 
    Private Sub ИвановоToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ИвановоToolStripMenuItem.Click
        Dim fName As String = IO.Path.Combine(Application.StartupPath, "tst.txt")
        Dim records() As String = IO.File.ReadAllLines(fName, System.Text.Encoding.Default)
        Dim bb As New List(Of Biography)
        For Each rr As String In records
            bb.Add(New Biography(rr.Split(","c)))
        Next
        Dim sel = From b As Biography In bb Where b.Город = "Иваново"
        DataGridView1.DataSource = Nothing
        If sel.Count > 0 Then
            DataGridView1.DataSource = sel.ToArray
        Else
            MsgBox("Нет данных!")
        End If
    End Sub
 
    Private Sub ВладимирToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ВладимирToolStripMenuItem.Click
        Dim fName As String = IO.Path.Combine(Application.StartupPath, "tst.txt")
        Dim records() As String = IO.File.ReadAllLines(fName, System.Text.Encoding.Default)
        Dim bb As New List(Of Biography)
        For Each rr As String In records
            bb.Add(New Biography(rr.Split(","c)))
        Next
        Dim sel = From b As Biography In bb Where b.Город = "Владимир"
        DataGridView1.DataSource = Nothing
        If sel.Count > 0 Then
            DataGridView1.DataSource = sel.ToArray
        Else
            MsgBox("Нет данных!")
        End If
    End Sub
 
    Private Sub DataGridView1_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellClick
        Dim index As Integer
        index = e.RowIndex
        Dim selectedrow As DataGridViewRow
        selectedrow = DataGridView1.Rows(index)
        TextBoxFIO.Text = selectedrow.Cells(0).Value.ToString
        TextBoxDen.Text = selectedrow.Cells(1).Value.ToString
        TextBoxMesyac.Text = selectedrow.Cells(2).Value.ToString
        TextBoxGOD.Text = selectedrow.Cells(3).Value.ToString
        TextBoxGorod.Text = selectedrow.Cells(4).Value.ToString
        TextBoxTel.Text = selectedrow.Cells(5).Value.ToString
        TextBoxMail.Text = selectedrow.Cells(6).Value.ToString
    End Sub
End Class
Public Class Biography
    Public Sub New(ByVal pp() As String)
        _ФИО = pp(0)
        _ДеньДР = CInt(pp(1))
        _МесяцДР = CInt(pp(2))
        _ГодДР = CInt(pp(3))
        _Город = pp(4)
        _Телефон = CLng(pp(5))
        _Почта = (pp(6))
    End Sub
    Public Property ФИО As String
    Public Property ДеньДР As Integer
    Public Property МесяцДР As Integer
    Public Property ГодДР As Integer
    Public Property Город As String
    Public Property Телефон As Long
    Public Property Почта As String
End Class

    Private Sub SaveButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SaveButton.Click
        Dim fName As String = IO.Path.Combine(Application.StartupPath, "tst1.txt")
        Dim records() As String = GetAllBioAsString(BindingSource1.List)
        IO.File.WriteAllLines(fName, records, System.Text.Encoding.Default)
    End Sub
 
    Private Function GetAllBioAsString(ByVal source As IEnumerable(Of Biography)) As String()
        Dim result As String() = {}
        Dim i As Integer
 
        For Each bio As Biography In source
            ReDim Preserve result(i)
            result(i) = bio.ToString
            i += 1
        Next
 
        Return result
    End Function

    Public Overrides Function ToString() As String
        Dim sep As String = ","
        Return ФИО & sep & ДеньДР & sep & МесяцДР & sep & ГодДР & sep & Город & sep & Телефон & sep & Почта
    End Function

Dim records() As String = GetAllBioAsString(BindingSource1.List)

Dim records() As String = GetAllBioAsString(bb)

Imports System.Reflection
'…
DataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.None
SetDoubleBuffered(DataGridView1)
'…
Public Sub SetDoubleBuffered(ByVal cntr As Control)
    GetType(Control).InvokeMember("DoubleBuffered", BindingFlags.SetProperty Or BindingFlags.Instance Or BindingFlags.NonPublic, Nothing, cntr, New Object() {True})
End Sub