/// <summary>
        /// Gets the default namespace for the folder minus the project's DefaultNamespace and minus the
        /// GetServiceArtifactsRootFolder() (i.e. "Service References").
        /// </summary>
        private string GetFolderDefaultNamespace(ProjectItems items)
        {
            string folderDefaultNamespace = null;

            // Try to get the 'default namespace' of the folder.
            ProjectItem parentItem = items.Parent as ProjectItem;

            if (parentItem != null)
            {
                Property folderDefaultNamespaceProperty = parentItem.Properties.OfType <Property>().FirstOrDefault(p => string.Equals(p.Name, "DefaultNamespace", StringComparison.OrdinalIgnoreCase));
                folderDefaultNamespace = folderDefaultNamespaceProperty?.Value as string;
                if (!string.IsNullOrEmpty(folderDefaultNamespace))
                {
                    // trim off the project's DefaultNamespace
                    string projectDefaultNamespace = this.context.ProjectHierarchy.GetDefaultNamespace();
                    folderDefaultNamespace = AzureIoTHubConnectedServiceHandlerHelper.TrimNamespacePrefix(folderDefaultNamespace, projectDefaultNamespace);

                    // trim off the service artifacts root folder name
                    string serviceRootArtifactNamespace = TokenReplacementBuilder.MakeSafeIdentifier(this.GetServiceArtifactsRootFolder());
                    folderDefaultNamespace = AzureIoTHubConnectedServiceHandlerHelper.TrimNamespacePrefix(folderDefaultNamespace, serviceRootArtifactNamespace);
                }
            }

            return(folderDefaultNamespace);
        }