求教，clientdataset主从表排序问题，盼高人解答。(200分)

2个表通过2个clientdataset做成前端主从表，在网上找了排序的函数，对结果集排序。主表正常，从表不行。百度了一下没有找到解决办法，各位高人可有遇到类似问题？ <br>下面是我用到的排序函数： <br>procedure TForm1.OrderGrid(dataSet:TClientDataset;orderField:string); <br>var <br>&nbsp; i:integer; <br>begin <br>&nbsp; if dataSet.IndexFieldNames &lt;&gt;'' then <br>&nbsp; begin <br>&nbsp; &nbsp; i:=TClientDataSet(DataSet).IndexDefs.IndexOf('i'+orderField); <br>&nbsp; &nbsp; if i=-1 then <br>&nbsp; &nbsp; begin <br>&nbsp; &nbsp; &nbsp; with Dataset.IndexDefs.AddIndexDef do <br>&nbsp; &nbsp; &nbsp; begin <br>&nbsp; &nbsp; &nbsp; &nbsp; Name:='i'+orderField; <br>&nbsp; &nbsp; &nbsp; &nbsp; Fields:=orderField; <br>&nbsp; &nbsp; &nbsp; &nbsp; DescFields:=orderField; <br>&nbsp; &nbsp; &nbsp; end; <br>&nbsp; &nbsp; end; <br>&nbsp; &nbsp; dataSet.IndexFieldNames:=''; <br>&nbsp; &nbsp; dataSet.IndexName:='i'+orderField; <br>&nbsp; end <br>&nbsp; else <br>&nbsp; begin <br>&nbsp; &nbsp; dataSet.IndexName:=''; <br>&nbsp; &nbsp; dataSet.IndexFieldNames:=orderfield; <br>&nbsp; end; <br>end; <br>在DBGrid的ontitleclick里调用此函数，主表的DBGrid可正常排序，从表的DBGrid出错。 <br><br>期待高人指点！