// Custom class. class Clump<T> : List<T> { // Custom implementation of Where(). public IEnumerable<T> Where(Func<T, bool> predicate) { Console.WriteLine("In Clump's implementation of Where()."); return Enumerable.Where(this, predicate); } } static void AsEnumerableEx1() { // Create a new Clump<T> object. Clump<string> fruitClump = new Clump<string> { "apple", "passionfruit", "banana", "mango", "orange", "blueberry", "grape", "strawberry" }; // First call to Where(): // Call Clump's Where() method with a predicate. IEnumerable<string> query1 = fruitClump.Where(fruit => fruit.Contains("o")); Console.WriteLine("query1 has been created.\n"); // Second call to Where(): // First call AsEnumerable() to hide Clump's Where() method and thereby // force System.Linq.Enumerable's Where() method to be called. IEnumerable<string> query2 = fruitClump.AsEnumerable().Where(fruit => fruit.Contains("o")); // Display the output. Console.WriteLine("query2 has been created."); } // This code produces the following output: // // In Clump's implementation of Where(). // query1 has been created. // // query2 has been created.