soRecordset循环中删除研究

1. soRecordset rs_a = dv_a.Query("2>1", true, null, "");
2.                         if (rs_a != null)
3.                         {
4.                             int rsCnt = rs_a.RecordCount;
5.                             if (rsCnt > 0)
6.                             {
7.                                 rs_a.MoveLast();
8.                                 for (int i = rsCnt;i>0 ; i--)
9.                                 {
10.                                     //Console.WriteLine(rs_a.GetFieldValueText ("smid"));
11.                                     Console.WriteLine(rs_a.GetID());
12.                                     if (i == 3)
13.                                     {
14.                                         rs_a.Delete();
15.                                         Console.WriteLine(rs_a.GetID());
16.                                     }
17.                                     rs_a.MovePrev();
18.                                 }
19.                             }
20.                             Marshal.ReleaseComObject(rs_a);
21.                             rs_a = null;

结论，删除之后，指向空，此时moveprev就是指向上一条记录，但是recordcount减少