index column negative

Need to copy row from one table to another

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();  

    }