DTE.ProjectItem GetChildItem(global::EnvDTE.ProjectItems projectItems, string name)
 {
     return projectItems
         .OfType<DTE.ProjectItem>()
         .SingleOrDefault(item => item.Name == name);
 }
 DTE.ProjectItem GetFirstChildItem(global::EnvDTE.ProjectItems projectItems)
 {
     return projectItems.OfType<DTE.ProjectItem>().FirstOrDefault();
 }
 List<DTE.ProjectItem> GetAllChildItems(global::EnvDTE.ProjectItems projectItems)
 {
     return projectItems.OfType<DTE.ProjectItem>().ToList();
 }