using System;

using System.Linq;

using System.Collections;

​

public class Program

{

    public static void Main()

    {

        IList mixedList = new ArrayList();

        mixedList.Add(0);

        mixedList.Add("One");

        mixedList.Add("Two");

        mixedList.Add(3);

        mixedList.Add(new Student() { StudentID = 1, StudentName = "Bill" });

        var stringResult = from s in mixedList.OfType<string>()

                           select s;

        var intResult = from s in mixedList.OfType<int>()

                           select s;

        var stdResult = from s in mixedList.OfType<Student>()

                           select s;

        foreach (var str in stringResult)

            Console.WriteLine(str);

        foreach (var integer in intResult)

            Console.WriteLine(integer);

        foreach (var std in stdResult)

            Console.WriteLine(std.StudentName);

    }

}

​

public class Student{

​

    public int StudentID { get; set; }

    public string StudentName { get; set; }

    public int Age { get; set; }

}