Description: Change master page programmatically

Link: http://www.codekeep.net/snippets/6ad7047e-c32b-40bc-b6c6-48b154efec73.aspx

var newMaster = properties.Feature.Properties["MasterName"].Value;

			    if (!string.IsNullOrEmpty(newMaster))
				{
					using (var curSite = (SPSite)properties.Feature.Parent)
					{
                        using (var curWeb = curSite.OpenWeb(""))
                        {
                            //got the current site and root web in site, now set the master Url
                            //to our master page that should have been uploaded as part
                            //of our feature
                            if (curWeb.MasterUrl.Contains("default.master"))
                            {
                                curWeb.MasterUrl = curWeb.MasterUrl.Replace("default.master", newMaster);
                                curWeb.Update();
                                UpdateLog("MasterUrl property updated for web " + curWeb.Title,
                                    EventLogEntryType.Information);
                            }

                        }
					}
				}