My xampp config

httpd-vhosts.conf

# xampp/apache/conf/extra/httpd-vhosts.conf
# You can replace the contents or append this

NameVirtualHost *:80

UseCanonicalName Off

 #
# My {sites-directory} is C:\xampp\htdocs\domains\ (full path)
# In the domains dir, I create a new dir for a new site
# No extension needed, so for example.dev create dir "example"
# now works with subdomain multisite. simply forwards foo.bar.dev too the "bar" directory
#

<VirtualHost *:80>
    ServerAlias localhost *.*.dev
    VirtualDocumentRoot C:/xampp/htdocs/domains/%1
    UseCanonicalName Off
</VirtualHost>

<VirtualHost *:80>
    ServerAlias localhost *.dev
    VirtualDocumentRoot C:/xampp/htdocs/domains/%-2+
    UseCanonicalName Off
</VirtualHost>

httpd.conf

# xampp/apache/conf/httpd.conf
# Obviously don't just replace your .conf with this
# Just search for vhosts.conf and make sure the Include isn't commented out

# Virtual hosts
Include conf/extra/httpd-vhosts.conf