C# this关键字

this 关键字引用类的当前实例，还可用作扩展方法的第一个参数的修饰符。

对实例的引用略过，下面给出扩展方法的例子：

 public static ObservableCollection<T> ArrayToObservableCollection<T>( this T[] list)
        {
            if (list == null)
                return null;
            ObservableCollection<T> collections = new ObservableCollection<T>();
            foreach (var item in list)
            {
                collections.Add(item);
            }
            return collections;
        }

        public static ObservableCollection<T> ListToObservableCollection<T>(this List<T> list)
        {
            if (list == null)
                return null;
            ObservableCollection<T> collections = new ObservableCollection<T>();
            foreach (var item in list)
            {
                collections.Add(item);
            }
            return collections;
        }

        public static List<T> ObservableCollectionToList<T>(this ObservableCollection<T> col)
        {
            if (col == null)
                return null;
            List<T> lst = new List<T>();
            foreach (var item in col)
            {
                lst.Add(item);
            }
            return lst;
        }