private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
        {
            if (dataGridView1.SelectedRows.Count > 0)
            {
                DataGridViewRow row = dataGridView1.SelectedRows[0];
                int             id  = (int)row.Cells[PurchaseCounterIdColumn.Name].Value;

                AddPurchaseCounterForm f = new AddPurchaseCounterForm();
                f.PurchaseCounterId = id;
                f.Show();
            }
        }
        private void AddButton_Click(object sender, EventArgs e)
        {
            AddPurchaseCounterForm form = new AddPurchaseCounterForm();

            form.Show();
        }