关于DataGridView显示的一个奇怪问题。

我用WinFrom的DataGridView显示一组数据，数据源是RowCount为6的数组，所以e.RowIndex应该是从0～5，可奇怪的是e.RowIndex数到4程序就跳出了，没有走到5，所以结果造成界面显示5组数据，少了一组，请问高人，这是怎么回事？（DataGridView.RowCount我设为6）   万分感谢！ 代码如下：
private void dgCurrExcgRate_CellValueNeeded(object sender, DataGridViewCellValueEventArgs e)
        {
            if (currExchangeRate != null)
            {
                if (e.RowIndex >= 0 && e.RowIndex < GetCount() )
                {
                    //DataScenarioCurrencyItem currentRow = currExchangeRate[e.RowIndex];
                    DataScenarioCurrencyItem currentRow = currExchangeRate[e.RowIndex];
                    switch (this.dgCurrExcgRate.Columns[e.ColumnIndex].Name)
                    {
                        case "currName":
                            //e.Value = currentRow.Scenario_curr_ISO;
                            e.Value = currentRow.Scenario_curr_ISO;
                            break;
                        case "ref_exchangeRate":
                            //e.Value = LocalizationUtil.FormatMoneyToString(currentRow.Scenario_curr_xchg_rate);
                            e.Value = LocalizationUtil.Format4DecimalToString(currentRow.Reference_rate);
                            break;
                        case "scen_Scenario":
                            //e.Value = LocalizationUtil.FormatMoneyToString(currentRow.Scenario_curr_xchg_rate);
                            e.Value = LocalizationUtil.Format4DecimalToString(currentRow.Scenario_curr_xchg_rate);
                            break;
                        case "chkRateLock":
                            e.Value = currentRow.Scenario_curr_freeze_opt;
                            break;
                        default:
                            break;
                    }
                }
            }
        }