Do you have one site in you Umbraco installation or do you have more than one?

If you only have one I'm guessing......you what you want to do is get a list of all nodes that have a particular property?

This will give you the root node.

var umbracoContext = Umbraco.Web.UmbracoContext.Current;
var umbracoHelper = new Umbraco.Web.UmbracoHelper(umbracoContext);
rootnode = umbracoHelper.TypedContentAtRoot();

Then you can look for all nodes that are of a given document type (the document type that has the property your looking for)

like this:

var nodesyouwant = rootnode.Where(x => x.DocumentTypeAlias == "yourDocTypeAliasHere");

hope that helps. Ayo

Thanks guys! I got what I needed, a list of media-urls from the media picker on the node. I trying to test the url up against the IHttpHandler Context, so I can prevent someone to download a PDF which is extranet protected, under a specific extranet page. Not all pdfs on the solution, should be protected, so I needed some way to find the urls for the protected PDFs only. This was the last code I needed :-)

var umbracoHelper = new Umbraco.Web.UmbracoHelper(Umbraco.Web.UmbracoContext.Current);
   string _childrenName = "";
   string _childrenID = "";

   List<IPublishedContent> listOfNodeWithProperty = new List<IPublishedContent>();

   IEnumerable<IPublishedContent> rootNodes = umbracoHelper.TypedContentAtRoot();
   foreach (IPublishedContent rootNode in rootNodes)
   {
    listOfNodeWithProperty.AddRange(rootNode.Descendants().Where(x => x.HasProperty("documentChooser")));
   }

   foreach (var child in listOfNodeWithProperty)
   {
    _childrenID = child.GetPropertyValue("documentChooser").ToString();
    var media = umbracoHelper.TypedMedia(_childrenID);
    _childrenName += "/  " + media.Url();
   }
   return Content(_childrenName);

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