Today I share with you a small (but useful) piece of code 
.
Indeed, for now WinRT does not provide a method to test the existence of a specific file. You can only try/catch an GetFileAsync call and it can be disappointing.
So here is a little solution:
public async static Task<bool> FileExistsAsync(this StorageFolder folder, string name)
{
var files = await folder.GetFilesAsync();
return files.Any((f)=>
{
return f.Name == name;
});
}
To use it, just call the following code:
if (!await ApplicationData.Current.LocalFolder.FileExistsAsync(filename))
return;
StorageFile file = await ApplicationData.Current.LocalFolder.GetFileAsync(filename);