How can use the currently displayed node to filter a block-level view on that node's page?

I have parent/child relationship set up via Node Reference. A Child record can have a Parent record selected from a Node Reference field (this is optional -- I can have Parent-less Children as well).

I've created a Views block to appear on the Parent pages, below the content. It's going to show a table of all the Child nodes for that Parent. Problem is, right now it shows every Child node. I need to filter it for just the Parent being displayed.

What I need to be able to do is add a filter to this View to effectively say, "Only show the Child nodes that are assigned to the Parent being displayed on this page."

So, somehow I need to be able to get the Nid of the currently displaying node (which will be a Parent, in all cases when this block is displayed), and use that in a filter in my View.

How exactly can I do this?

(Initially I used an attachment view for this (as this page instructs). I created a page view to display the Parent, then an attachment view to display all the Children, t开发者_JAVA百科hen attached that under the page view. This worked, but it was almost absurdly complicated to set up, and it was an undesirable for a number of other reasons -- primarily that my Parent now has two dedicated URLs, it's own node-level page, and the similar page created by this view.)

Using Drupal 6.15.

I found it. You add an argument for the Parent relationship, then supply a default value of "Node ID from the URL."