To start with, those rules appear to do the opposite of what you say you want - i.e. they're rewriting "/localhost/casino2/news/4711" to "/casino2/newsdetail.php?newsid=4711".
Provided this is what you really mean, what you need to do is to save two items into two variables, instead of just one into one variable, like this:
RewriteRule ^news/([^/]+)/([^/]+) /casino2/newsdetail.php?newsid=$1&pagename=$2 [NC]
If the newsid is always 1, so that you don't need to pass it to the php, you simply create it in your replacement, like this
RewriteRule ^news/([^/]+) /casino2/newsdetail.php?newsid=1&pagename=$1 [NC]
This would create the following rewrites:
/news/article -> /casino2/newsdetail.php?newsid=1&pagename=article
/news/somethingelse -> /casino2/newsdetail.php?newsid=1&pagename=article
But if you want to be able to select different newsids, you need to pass it in somewhere - either as part of the URL or as a querystring.
Just to be clear, the way the rules are applied is
RewriteRule "What the URL looks like in the browser" "What my web server expects"
If you have problems, I highly suggest you turn on a lot of debug logging, it'll be a great help. The relevant config lines are
RewriteLog /path/to/logfile
RewriteLogLevel 3