C#

using (IsolatedStorage storage = IsolatedStorage.GetUserStorForDomain())
{
  using (IsolatedStorageFileStream fs = new IsolatedStorageFileStream("MySession.xml", FileMode.Create, storage)
  {
    // Write the "cookie"...
    fs.Close();
  }
}

using (IsolatedStorage storage = IsolatedStorage.GetUserStorForDomain())
{
  using (IsolatedStorageFileStream fs = new IsolatedStorageFileStream("MySession.xml", FileMode.Open, storage)
  {
    // Read the "cookie"...
    fs.Close();
  }
}

treeView.Nodes[rootIndex].Nodes.Add(...);
treeView.Nodes[rootKey].Nodes.Add(...);

Assembly theAssembly;
theAssembly = Assembly.LoadFrom("TheDll.dll"); 
Type theType = theAssembly.GetType("TheType");
// or: Type theType = theAssembly.GetTypes()[0] as I know that there will surely be just one Type in the namespace

Type theType = Assembly.LoadFrom("TheDll.dll").GetTypes()[0]

angelsherin wrote:

What i suppose to do is to use list of arraylists

  class Program
    {
        static void Main(string[] args)
        {
            List<product> myList = new List<product>();

            myList.Add(new Book("Beginners C#", "Some author"));
            myList.Add(new Book("Advanced C#", "Anon author"));
            myList.Add(new Book("Expert gardening", "Mr Carrot"));
            myList.Add(new Book("Step by step guide to plane building", "Mr S. Pitfire"));

            myList.Add(new Mobile("Nokia N70", true, 3));
            myList.Add(new Mobile("Sony W810", false,2));

            var query = from b in myList
                        where b is Book
                        select b as Book;

            foreach (Book book in query)
            {
                Console.WriteLine(book.ProductDescription + " by " + book.Author);
            }

            Console.ReadLine();
        }
    }

    public class Product
    {
        private String _productDescription;

        public Product(String productDescription)
        {
            _productDescription = productDescription;
        }

        public String ProductDescription
        {
            get
            {
                return _productDescription;
            }
            set
            {
                _productDescription = value;
            }
        }
	
    }

    public class Book : Product
    {
        private String _author;

        public Book(String productDescription, String author)
            : base(productDescription)
        {
            _author = author;
        }

        public String Author
        {
            get
            {
                return _author;
            }
            set
            {
                _author = value;
            }
        }
	
    }

    public class Mobile : Product
    {
        private bool _is3G;
        private int _cameraMegaPixels;

        public Mobile(String productDescription, bool is3G, int cameraMegaPixels)
            : base(productDescription)
        {
            _is3G = is3G;
            _cameraMegaPixels = cameraMegaPixels;
        }

        public int CameraMegaPixels
        {
            get
            {
                return _cameraMegaPixels;
            }
            set
            {
                _cameraMegaPixels = value;
            }
        }
	

        public bool Is3G
        {
            get
            {
                return _is3G;
            }
            set
            {
                _is3G = value;
            }
        }
	
    }
</product></product>