void NotifyFileAddedToProject (IEnumerable<ProjectFile> objs)
{
if (!objs.Any ())
return;
var args = new ProjectFileEventArgs ();
foreach (ProjectFile file in objs) {
if (file.Project != null)
throw new InvalidOperationException ("ProjectFile already belongs to a project");
file.SetProject (this);
args.Add (new ProjectFileEventInfo (this, file));
ResolveDependencies (file);
}
NotifyModified ("Files");
OnFileAddedToProject (args);
}