public CimExtensionViewModel()
 {
     AddCommand    = new RelayCommand(() => Contents.Add(Content));
     DeleteCommand = new RelayCommand(() => Contents.Remove(SelectedContent));
     SaveCommand   = new RelayCommand(() =>
     {
         CimExtensionService.GetInstance().Save();
         MessageBox.Show("保存完成");
     });
 }
 public static CimExtensionService GetInstance()
 {
     if (_instance == null)
     {
         lock (_locker)
         {
             if (_instance == null)
             {
                 _instance = new CimExtensionService();
             }
         }
     }
     return(_instance);
 }