fixed NRE when using search-box

[XiaotianNetlift]

Issue: #50

PR Type

What kind of change does this PR introduce?

• Bugfix

What is the current behavior?

The app crash when trying to use the search-box.

What is the new behavior?

The app shouldn't crash

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• Pull Request has been submitted to the documentation repository instructions. Link:
• Sample in sample app has been added / updated (for bug fixes / features)
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• Tests for the changes have been added (for bug fixes / features) (if applicable)
• Header has been added to all new source files (run build/UpdateHeaders.bat)
• Contains NO breaking changes

Other information

same vein as: #54

[XiaotianNetlift]

/azp run