Um...D:\Projects\MyWPF\ is very unlikely to be your data directory - and it's very, very likely to cause problems in production when installed on another machine - because your app will be in the "Program Files" folder and writing that that is either difficult or impossible for security reasons.
Have a look at this:
Where should I store my data?[
^] - it suggests some better places which would be appropriate for development and release.
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