MvvmCross/MvvmCross — pull request #798 by vegardlarsen (2014-10-13 11:24:38+00:00)
Title: Performance fix for checking if file exists

The current implementation of Windows Store and Windows Common enumerates all the files in the folder when checking if a single file exists. This is a huge performance drain if the folder contains many files.

The correct way to do this is to try to open the file, and if it throws `FileNotFoundException`, we can `return false`.