HairNet does not yet work in Blender 2.80. It appears that a bug in Blender is keeping it from working. It should be resolved eventually, but there's no way to set a schedule for when.
HairNet for 2.79 still works.
HairNet addon for Blender
Blender Wiki page: https://en.blender.org/index.php/Extensions:2.6/Py/Scripts/Objects/HairNet
Blenderartists Thread: https://blenderartists.org/t/hair-guides-created-from-mesh-objects/572642
Installation: Visit the "Releases" page and download version 0.5.1. https://github.com/Jandals/HairNet/releases
Then use Blender's "User Preferences" window to "Install Addon From File." Choose the ZIP file you just downloaded and that should be all.