gappie, I think using ListItem would be too much work. You can only use it to return a single specified value, say, the first, or the second or third etc. genre in the field. It won't break the whole thing down and present a list for you.
antipode, MC has several types of [Field].
The default [Genre] field is a standard "string type" field. IE, it can only hold a single string value. MC's default fields cannot be edited.
To realise a field containing multiple genres, you would need to manually create a "semi colon delimited list type" field and then configure your view scheme(s) to show your new field.
To create a new field:
open MC's options and select Library and folders: Tools > Options > Library and Folders.
select "user library fields" in the right hand pane.
click on "add field" and fill the dialogue like so:
the keyword entry is purely optional. they help speed up searches, so, rather than type [genres]=rock in the search bar, gs=rock will return the same result.
The field name is also completely optional. You may call it whatever you wish so long as you don't use an existing field name.
OK your way out of options.
load a view where you'd like to see [genres].
list type fields are not really designed to work as columns, so you'd want to add a Genres pane. (columns make up the file list at the bottom of a view, while panes are shown at the top.)
click on a pane header next to where you want Genres to be and you will see, among others, add pane to left or add pane to right of this one. Choose appropriately and then choose Genres from the list of library fields.
You may also want to see Genres in the Tag action window (bottom left of MC) and to do that, right click in the tag window and follow the "Also show..." menu.
Start adding Genres. You can do this by selecting files, then clicking in the little boxes you see in the Genres pane. (to begin with of course, you will only see "New Genres") or by clicking on "Genres" in the tag window.
-marko.