如何检查datarowview是否已存在记录？

Question

DataRowView rvTbl;

BindingSource bs = new BindingSource();
bs.DataSource = dsData1;
bs.DataMember = _sheetname;

Excel.Worksheet _workSheet = (Worksheet)_workbook.Worksheets.get_Item(_sheetIndex);
Range rangerow in _workSheet.UsedRange.Rows

上面是定义

bs.CurrencyManager.AddNew();
rvTbl = (DataRowView)bs.CurrencyManager.Current;
ctr = 0;

    for (int i = 0; i < rangerow.Columns.Count; i++)
    {
        if (rangerow.Cells[1, i + 1].Value2 != null)
        {
            rvTbl[fLine[ctr]] = rangerow.Cells[1, i + 1].Value2.ToString();
            MessageBox.Show(Convert.ToString(rvTbl[fLine[ctr]]));
            ctr++;
        }
    }
    bs.CurrencyManager.EndCurrentEdit();

以上是我的处理导入文件并填充数据的代码，我的问题是“是否有办法检查数据是否已存在？”我该怎么办？