private void button4_Click_1(object sender, EventArgs e) { Deadlines deadlines = new Deadlines(SQL); deadlines.Add(dateTimePicker1.Value); Deadline deadline = deadlines.GetLast(); Status = "Naskladňuji..."; foreach (DataGridViewRow row in dataGridView1.Rows) { int id = 0; if ((row.Cells["IDColumn"].Value != null) && (int.TryParse(row.Cells["IDColumn"].Value.ToString(), out id) == true)) { Transfer item = Transfers.GetRecord(id); item.Deadline = deadline; Transfers.Change(item); } } Status = "...."; dataGridView1.Enabled = false; button4.Enabled = false; }