You just created an empty file which MS Excel cannot recognize. The file may have the right extension but it's not of MS Excel format.
Please go to the following site as they provide information on how to automate Excel tasks with C#.
You can use Excel C# interop to create the file but that also means that the computer running your application needs to have MS Excel installed.
http://support.microsoft.com/kb/302084[
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Here is a link exploring an option when Excel is not installed on the computer running the application:
http://p2p.wrox.com/c/1745-create-excel-file-without-excel-being-installed.html[
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Regards,
Manfred