多層結構中數據更新過程無法完成？(100分)

　　

在客户端数据集中加事件，（参考如下）
procedure TfrmInsertPic.ClientDataSetAfterPost(DataSet: TDataSet);
var
cdsMaster: TClientDataSet;
begin
cdsMaster := TClientDataSet(DataSet);
while cdsMaster.DataSetField <> nildo
cdsMaster := TClientDataSet(cdsMaster.DataSetField.DataSet);
cdsMaster.ApplyUpdates(0);
end;

procedure TfrmInsertPic.ClientDataSetAfterDelete(DataSet: TDataSet);
var
cdsMaster: TClientDataSet;
begin
cdsMaster := TClientDataSet(DataSet);
while cdsMaster.DataSetField <> nildo
cdsMaster := TClientDataSet(cdsMaster.DataSetField.DataSet);
cdsMaster.ApplyUpdates(0);
end;