主题：有劳

Dim filter As String = "1=1"
For Each dc As DataCol In DataTables("表A").DataCols
    filter &= " and " & dc.Name & " Is not null"
Next
Dim fdr As DataRow = DataTables("表A").Find(filter, "_sortkey")
Dim sidx As Integer = Tables("表A").FindRow(fdr)
fdr = DataTables("表A").Find(filter,"_sortkey desc")
Dim eidx As Integer = Tables("表A").FindRow(fdr)
For i As Integer = Tables("表A").Rows.Count - 1 To 0 Step -1
    If i < sidx OrElse i > eidx Then
        Tables("表A").Rows(i).delete
    End If
Next

有点小毛病，全部删除。遍历要加一个条件。

 遍历是所有的列啊，你要所有的列都有数据才能保留啊。