Problem about size with creating excel file using xml spreadsheet ?

[C# Programming]

Hi everyone,

I am creating XML spreadsheet in C# and save it as Excel file (.xls). After creating, I have a excel with the size is: 500KB

But, after opening it and click "save" button without changes, the new size is: 2.5MB

Are there anyone know why and how to fix it ?

Please see my excel file at the link: http://www.mediafire.com/?5irdbchc10nonq4[^ (http://www.mediafire.com/?5irdbchc10nonq4)]

Thanks and regards,
Tai