exele veri update etme

public void excel()
{
Excel.Application ExcelNesnesi = new Excel.Application();
if (ExcelNesnesi == null)
{
MessageBox.Show("Excel Cort!");
}

ExcelNesnesi.Workbooks.Add(true);
ExcelNesnesi.Visible = true;
Excel.Worksheet tablo;
tablo = (Excel.Worksheet)ExcelNesnesi.ActiveSheet;
if (Convert.ToBoolean(oleDbConnection1.State) != true)
{
oleDbConnection1.Open();
}
oleDbCommand1.Connection = oleDbConnection1;
oleDbCommand1.CommandText = "SELECT Ad, Soyad, [Ev Telefon], [Cep Telefon], Adres, [Müşteri No]" +
"FROM Musteri";
OleDbDataReader oku;
int i = 1;
oku = oleDbCommand1.ExecuteReader();
tablo.Cells[i, 1] = "Musteriler";

while (oku.Read())
{
i++;
tablo.Cells[i, 1] = Convert.ToString(oku.GetString(0).Trim().ToString());


}
oku.Close();
i = 2;

oku = oleDbCommand1.ExecuteReader();
while (oku.Read())
{
tablo.Cells[i, 2] = oku.GetString(1);
i++;
}
oku.Close();
i = 2;
oku = oleDbCommand1.ExecuteReader();
while (oku.Read())
{
tablo.Cells[i, 3] = oku.GetString(2);
i++;
}
oku.Close();
i = 2;
oku = oleDbCommand1.ExecuteReader();
while (oku.Read())
{
tablo.Cells[i, 4] = oku.GetString(3);
i++;
}
oku.Close();
i = 2;
oku = oleDbCommand1.ExecuteReader();
while (oku.Read())
{
tablo.Cells[i, 5] = oku.GetString(4);
i++;

}
oku.Close();
i = 2;
oku = oleDbCommand1.ExecuteReader();
while (oku.Read())
{
tablo.Cells[i, 6] = oku.GetInt32(5);
i++;
}


}