System.Configuration.SettingsBase.this C# (CSharp) Метод

       public virtual object this[string propertyName]
       {
           get {
               if (IsSynchronized) {
                   lock (this) {
                       return GetPropertyValueByName(propertyName);
                   }
               } else {
                   return GetPropertyValueByName(propertyName);
               }
           }
           set {
               if (IsSynchronized) {
                   lock (this) {
                       SetPropertyValueByName(propertyName, value);
                   }
               } else {
                   SetPropertyValueByName(propertyName, value);
               }
           }
       }