IMHO the real problem is that .NET does not run on all operating systems. That's why we needed Mono on Linux. For a .NET application to work on arbitrary operating systems you would need .NET Core.
Problem here: Microsoft does not provide the means to implement a GUI in .NET Core until version 3. With version 3 you get WinForms and WPF support, but those ...
This answer focuses on the data, not on any particular app.
You could use the Wikidata Query Service to get started:
Pictures of fruit - see Picture captions for Links to Fruit Properties:
https://w.wiki/3SCk or https://w.wiki/3SCt
#Fruit, with pictures
SELECT ?item ?itemLabel ?pic
?item wdt:P31 wd:Q3314483 .
?item wdt:P18 ?pic