Update Scenario1_BasicFunctionality.xaml.cs

[LanceMcCarthy]

This fixes the problem discussed in this documentation fix MicrosoftDocs/windows-dev-docs#681

The documentation has been updated, this sample should also be updated with the fix

[oldnewthing]

This isn't quite right, because you don't have to start the software trigger. The hardware trigger still works (and is recommended since it uses less power). Will need to add checkbox to select whether to scan continuously or to scan only when hardware trigger is pressed.

[LanceMcCarthy]

Thanks Raymond. Should I just add that to my branch? I can add the checkbox to enable/disable software scanning so we can keep it in this PR to maintain context.

[oldnewthing]

I'll add this to the list of things for me to do (it's sort of already on the list, since it's an open PR). I'll need to port the sample to C++/WinRT first.