// import common useful library references... often from .NET Framework, then your own classes; this must be at the top of the source file

using System;

using System.Collections;

using System.Collections.Generic;

using System.Collections.Specialized;

using System.Linq;

​

// Classes, the "object oriented" way of exposing related variables and functionality in your app

// Lets you build smart objects that other developers interact with

// Only exposes what you want exposed

​

// Helper function to print the list in a sorta pretty way.

void printList(List<Person> list)

{

    foreach (var person in list)

    {

        Console.WriteLine(person.FirstName);

    }

        Console.WriteLine();

}

​

class Person

{

    string _firstName; // has a default value of Empty String and is PRIVATE

    string _lastName;   

    string _phoneNumber;

​

    public Char MiddleInitial { get; set; } // note this *Property* is public

​

    public String FirstName // another public property, ENFORCING BUSINESS RULES

    {

        get {

            return _firstName;

        }

        set {

            _firstName = value.Trim(); // clean up values before we store them - this is a "business rule"

        }

    }

    public String LastName { get { return _lastName; } } 

    public Person()

    {

        // Default constructor.

    }

    public Person(String f, String l, String p)

    {

        _firstName = f;

        _lastName = l;

        _phoneNumber = p;

    }

}

​

var people = new List<Person>() {

    new Person("Auri", "Rahimzadeh", "317.490.4321"),

    new Person("Steve", "Wozniak", "408.555.1212"),

    new Person("Scott", "Jones", "818.555.1212"),

    new Person("Daishaun", "Paschall", "800.555.1212"),

    new Person("John", "Doe", "317.490.4321"),

    new Person("Mary", "Smith", "408.555.1212"),

    new Person("Geoff", "Smith", "818.555.1212"),

    new Person("Doug", "Smith", "800.555.1212")

};

​

// Function pointer could be passed instead

bool DoWhere(Person person)

{

    return person.FirstName.Contains("S");

}

​

var result = people

    .Where(w => w.FirstName.Contains("S"))

    .OrderByDescending(o => o.FirstName)

    .ToList();

​

result = (from p in people

         where p.FirstName.StartsWith("S")

         select p).OrderBy(o => o.FirstName).ToList();

​

​

// Additive queries.

​

/*

var onlyGetSmiths = true;

var onlyS = true;

​

var query = people.AsQueryable();

​

if (onlyGetSmiths) {

    query = query.Where(w => w.LastName == "Smith");

}

​

if (onlyS) {

    query = query.Where(w => w.FirstName.Contains("S"));

}

​

printList(query.ToList());

*/

​

// Where, First, FirstOrDefault, Single, SingleOrDefault

// Select

// OrderBy, ThenBy, Except, ToArray and ToList with Casting

​

var person = people.SingleOrDefault(f => f.FirstName.Contains("X"));

​

Console.WriteLine(person != null ? person.FirstName : "Couldn't find a match." );

​

​

Console.WriteLine(people.Count(c => c.FirstName.Contains("S")) > 0);

Console.WriteLine(people.Any(c => c.FirstName.Contains("S")));

​

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