using CMS.TreeEngine;

using CMS.CMSHelper;

int nodeId = 241;

double rating = 1.0f;

int numOfRatings = 2;

// Get the document

TreeProvider tree = new TreeProvider(CMSContext.CurrentUser);

CMS.TreeEngine.TreeNode node = tree.SelectSingleNode(nodeId, CMSContext.PreferredCultureCode);

// Modify its rating

TreeProvider.SetRating(node, rating, numOfRatings);