主题：随机抽查凭证

以下代码的帮助的代码，想实现在指定科目编号的凭证明细抽查指定数量的凭证，代码怎么修改？

Dim drs As List (of DataRow) = DataTables("凭证明细").Select("科目编号 = '"& CurrentTable.current("科目编号") & "'")
Dim cnt As Integer = DataTables("凭证明细").DataRows.Count
Dim nds As Integer = 100 '要抽取的记录数
Tables("凭证明细").StopRedraw()
DataTables("凭证明细").ReplaceFor("选择",False)
Do
    Dim idx As Integer = rand.Next(0,cnt)
    Dim dr As DataRow = DataTables("凭证明细").DataRows(idx)
    If dr("选择") = False Then
        dr("选择") = True
        nds = nds - 1
    End If
Loop While nds > 0
Tables("凭证明细").Filter = "[选择] = True"
Tables("凭证明细").ResumeRedraw()

Dim drs As List (of DataRow) = DataTables("凭证明细").Select("科目编号 = '"& CurrentTable.current("科目编号") & "'")
Dim cnt As Integer = drs.Count
Dim nds As Integer = 100 '要抽取的记录数
Tables("凭证明细").StopRedraw()
DataTables("凭证明细").ReplaceFor("选择",False)
Do
    Dim idx As Integer = rand.Next(0,cnt)
    Dim dr As DataRow = drs(idx)
    If dr("选择") = False Then
        dr("选择") = True
        nds = nds - 1
    End If
Loop While nds > 0
Tables("凭证明细").Filter = "[选择] = True"
Tables("凭证明细").ResumeRedraw()