SharePoint 2013 setting custom masterpage featureactivated not working

Question

I have used this code on many projects for 2010 on a site-scoped feature, and it has always worked:

public override void FeatureActivated(SPFeatureReceiverProperties properties)
{
    if (properties != null)
    {
        SPSecurity.RunWithElevatedPrivileges(delegate
        {
            using (SPWeb _web = ((SPSite)properties.Feature.Parent).RootWeb)
            {
                Uri _siteMaster = new Uri(string.Format("{0}/_catalogs/masterpage/CustomMaster.master", _web.Url));
                Uri _siteSystemMaster = new Uri(string.Format("{0}/_catalogs/masterpage/CustomMaster.master", _web.Url));

                _web.CustomMasterUrl = _siteMaster.AbsolutePath;
                _web.MasterUrl = _siteSystemMaster.AbsolutePath;

                // Use these properties to control the radio buttons
                _web.AllProperties["__InheritsCustomMasterUrl"] = "false";
                _web.AllProperties["__InheritsMasterUrl"] = "false";
                _web.AllProperties["__InheritsAlternateCssUrl"] = "false";

                _web.Update();
            }
        });
    }
}

But in 2013, it doesn't seem to work, meaning by activating the feature, the master doesn't get set in Site Settings -> Masterpage. I have debugged the feature, and all is well, so I'm not sure if this is just an issue for me, or if anyone else has run into the same issues. I'm not finding anything in the community about it, so I wanted to start the discussion here.

I should also mention that the site collection root web is based on a Publishing Portal site template with all subwebs inheriting their master.

Thanks in advance for taking a look!

Answer 1

A couple quick notes about your code:

• You do not need to dispose of the RootWeb object.
• You aren't elevating privileges at all if you cast the SPSite from the event receiver properties. You need to open a new instance of SPSite in the elevated code block, but privilege elevation isn't necessary at all here.
• Is your master page deployed to each SPWeb? Typically it's only deployed once to the site collection's root master page gallery and pulled from there. If you are duplicating the file across every sub site that is unnecessary.

Answer 2

this should do the trick.

public override void FeatureActivated(SPFeatureReceiverProperties properties)
{
     SPWeb Web = properties.Feature.Parent as SPWeb;

     Web.MasterUrl = Web.Site.RootWeb.ServerRelativeUrl + "/_catalogs/masterpage/CustomMaster.master";

     Web.CustomMasterUrl = Web.Site.RootWeb.ServerRelativeUrl + "/_catalogs/masterpage/CustomMaster.master";

     Web.Update();

     Web.Dispose();
}