internal IColumnObjectAccessor _CreateAccessor(string colName, IFrame frame)
 {
     if (frame is SimpleFrame)
         return new BlueSpider.Blob.Regular.Data.SimpleFrameColumnObjectAccessor(frame.IndexOfColumn(colName), (SimpleFrame)frame);
     else if (frame is BlueSpider.Blob.Data.CSpace.Frame)
         return new BlueSpider.Blob.Data.CSpace.FrameColumnObjectAccessor(frame.IndexOfColumn(colName), (BlueSpider.Blob.Data.CSpace.Frame)frame);
     return null;
 }