Hello!
I've got several mp3s in a folder, I select all and I press 'enter' to launch Windows Media player to listen. But Windows Media Player open one then close this one and open the next one ... for each files. So just one file is reading. I would like all the file being added to the playlist 
Media Player doesn't seem to have way to add files to the playlist via the command-line so you'd have to make Opus trigger the context menu "Queue-It-Up" command (assuming it exists for your version of Media Player -- Microsoft seem to have removed it from WMP10 according to the web, although I only have WMP9 here at work so I'm not sure).
In theory this command should do it:
ContextMenu WMPEnqueue
But it doesn't seem to do anything. 
Not sure why.
If you run
ContextMenu SHOWCMDS
while a music file is selected Opus will show you a list of the context-menu commands that you might be able to use in place of WMPEnqueue in my example. Give one of them a try if you're feeling lucky.
If anyone else is reading this and wants a similar button for Winamp or Foobar then they're both easy enough to setup since you can enqueue files from the command-line with those players. WMP's command-line seems to be quite limited.
I use WMP10. WMPEnqueue doesn't work, but I can use WMPAddToPlaylist 
(finded with showcmds).
Now I would like to use it automaticaly, without using a button.
In filetype options, with "mp3" in the category "open" I change :
"C:\Program Files\Windows Media Player\wmplayer.exe" /prefetch:6 /Open "%L"
by
"C:\Program Files\Windows Media Player\wmplayer.exe" /WMPAddToPlaylist
But when I open files pressing "enter" nothing new happen...
And if I find a solution for mp3s, would I have to do this for each files I open with WMP ??:lol: Is there anyway to copy the way how windows explorer works ? because this works for all files with windows explorer.
I think it should be just
ContextMenu WMPAddToPlaylist
rather than
"C:\Program Files\Windows Media Player\wmplayer.exe" /prefetch:6 /Open /WMPAddToPlaylist
Unless wmplayer.exe has some undocumented command-line arguments that match the context menu entries?
You could also try
"C:\Program Files\Windows Media Player\wmplayer.exe" /prefetch:6 /Open {allfilepath$}
which will give all of the filenames to WMP at once.
Nothing works... But it is strange, when I change "C:\Program Files\Windows Media Player\wmplayer.exe" /prefetch:6 /Open {allfilepath$}
by an other application, windows media player is still use.
Here is where I edit :
Is it correct ?
That looks fine, but check on the Events tab that nothing is overriding dblclk and also, from the main File Types list, check the Open With settings which can confuse things.
yes Open With settings may confuse things.
So... no way to do without button (like in windows explorer) ?
Thinking about it some more, if I remember right, WMP has a COM interface so you could do it via some VBScript. I don't have time to look at it right now though as it would take a bit of research/googling.