Error in my app...index column negativecsome help?

Question

Error is here line 11 and line 12

row = (DataGridViewRow)roba_uslugeDataGridView.SelectedRows[i].Clone(); int intColIndex = 0;

Some help?

Private void roba_uslugeDataGridView_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
{
    DataGridViewRow row = new DataGridViewRow();

    for (int i = 0; i < roba_uslugeDataGridView.Rows.Count; i++)
    {
        row = (DataGridViewRow)roba_uslugeDataGridView.SelectedRows[i].Clone();
        int intColIndex = 0;

        foreach (DataGridViewCell cell in roba_uslugeDataGridView.SelectedRows[i].Cells)
        {
            var ColIndex = dataGridView1.Rows.Add();
            dataGridView1.Rows[intColIndex].Cells["redni_broj"].Value = intColIndex + 1;
            dataGridView1.Rows[intColIndex].Cells["bar_kod"].Value = cell.Value.ToString();
            dataGridView1.Rows[intColIndex].Cells["sifra"].Value = cell.Value;
            dataGridView1.Rows[intColIndex].Cells["naziv_artikla"].Value = cell.Value;
            dataGridView1.Rows[intColIndex].Cells["cijena"].Value = cell.Value;
            dataGridView1.Rows[intColIndex].Cells["kolicina"].Value = "1";
            foreach (DataGridViewRow g1 in dataGridView1.Rows)
            {
                g1.Cells["ukupno"].Value = (Convert.ToDouble(g1.Cells["kolicina"].Value) * Convert.ToDouble(g1.Cells["cijena"].Value)).ToString("0.00");
            }
            row.Cells[intColIndex].Value = cell.Value;
            intColIndex++;
        }
        dataGridView1.Rows.Add(row);
    }
    dataGridView1.AllowUserToAddRows = false;
    dataGridView1.Refresh();

}