and returns all even numbers.public static IEnumerable<int> GetEven(IEnumerable<int> numbers)
匿名方法.匿名方法类似于函数式编程中的闭包。public void Foo(object parameter)
委托的协变和逆变.委托签名的协变和逆变,
属性访问器可以被单独设置访问级别.例子：string status = string.