由于DW2XLS原版本是完全采用PB的代码实现生成Excel文件的，在性能上有很大的限制，当导出的报表数据量比较大时，导出的时间会非常久。更严重的问题是，当数据量比较大时，最终生成的Excel文件格式是损坏的，用户不能正常打开生成的文件!
　　正是因为以上两大原因，并且希望导出的Excel文件格式更加完整、支持图片导出等功能，才决定重新开发DW2XLS组件程序。(Since the original version of DW2XLS is the complete use of PB code to generate Excel files, it is very limited in performance. When the output of report data is large, the time of export will be very long. A more serious problem is that when the amount of data is large, the resulting Excel file format is corrupted, and users can't normally open the generated files.
It is precisely because of the above two reasons, and we want to export the Excel file format more complete, support the picture export and other functions, then decided to redevelop the DW2XLS component program.)