dotNet_PredefinedDelegates

//Person Class

namespace DotNet_PredefinedDelegates
{

    public class Person
    {
        public string Firstname { get; set; }
        public string Lastname { get; set; }
        public DateTime DateOfBirth { get; set; }

        public override string ToString()
        {
            return Firstname + " " + Lastname;
        }
    }
}

//==================================================

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace DotNet_PredefinedDelegates

{

    public partial class Form1 : Form

    {

        /// <summary>

        /// .Net Generic Delegates

        /// Action<> delegates // All action delegates return a void

        /// read more... http://msdn.microsoft.com/en-us/library/system.action(v=vs.110).aspx

        /// Func<> delegates // All the Func delegates return a value of some type

        /// Predicate<> delegate //takes a single parameter of some type, but always returns a boolean

        /// </summary>

        List<int> intList = new List<int>();

        List<Person> personList = new List<Person>();

        Random rand = new Random();

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            //Initialize intList

            for (int i = 1 ; i <= 50; i++)

                intList.Add(rand.Next(-99, 100));

            //initialize personList

            Person p = new Person { Firstname = "John", Lastname = "Doe", DateOfBirth = new DateTime(1990, 11, 2) };

            personList.Add(p);

            p = new Person { Firstname = "Karen", Lastname = "Jordan", DateOfBirth = new DateTime(1979, 2, 23) };

            personList.Add(p);

            p = new Person { Firstname = "Amy", Lastname = "Johnson", DateOfBirth = new DateTime(1980, 8, 15) };

            personList.Add(p);

            p = new Person { Firstname = "Seng", Lastname = "Mary", DateOfBirth = new DateTime(1988, 4, 30) };

            personList.Add(p);

            p = new Person { Firstname = "David", Lastname = "Lama", DateOfBirth = new DateTime(2011, 7, 2) };

            personList.Add(p);

            p = new Person { Firstname = "Grace", Lastname = "Lama", DateOfBirth = new DateTime(2013, 11, 25) };

            personList.Add(p);

            p = new Person { Firstname = "Zau", Lastname = "Bawk", DateOfBirth = new DateTime(1985, 3, 17) };

            personList.Add(p);

            Display2(personList);

        }

        private void Display<T>(List<T> list)

        {

            richTextBox1.Clear();

            foreach (T num in list)

                richTextBox1.AppendText(num + "\n");

        }

        //=======================================

        private void Display2(List<Person> list)

        {

            richTextBox1.Clear();

            foreach (Person p in list)

            {

                richTextBox1.AppendText(String.Format(

                    "{0}   {1}    {2}", p.Firstname, p.Lastname,

                    p.DateOfBirth.ToShortDateString() + "\n"));

            }

        }

        private void btnGetOddValues_Click(object sender, EventArgs e)

        {

            //use the FindAll method to return all the odd values

            //eg. read more... http://msdn.microsoft.com/en-us/library/vstudio/fh1w7y8z(v=vs.100).aspx

            //public List<T> FindAll(Predicate<T> match)

            //The predicate delegate object match should be referencing a method that has the same

            //signature as the Predicate<T> delegate type

            //since the List is of type int, the T is int

            //The FindAll method will call the predicate (in this case the match object for 

            //every element int he list, then saves and returns

            //only the element for which the match returns true.

            //1. Create  Predicate <int> delegate object

            //Predicate<int> predicate = x => x % 2 != 0;

            //List<int> oddList = intList.FindAll(predicate);

            //or

            List<int> oddList2 = intList.FindAll(x => x % 2 != 0);

            //every element of the intList will be tested against the 

            //condition stated in the predicate, if the result is true

            //then the element is kept and returned 

            Display(oddList2);

        }

        private void btnFindnameWith4Letter_Click(object sender, EventArgs e)

        {

            //Get people with 4-Letter firstname

            Predicate<Person> predicate = p => p.Firstname.Length == 4;

            List<Person> shortfirstnamepeople = personList.FindAll(predicate);

            //Display<Person>(shortfirstnamepeople);

            Display2(shortfirstnamepeople);

        }

        private void btnGetPersonWithGivenBirthYear_Click(object sender, EventArgs e)

        {

            int birthYr;

            int.TryParse(txtBirthYear.Text, out birthYr);

            Predicate<Person> predicate = p => p.DateOfBirth.Year == birthYr;

            List<Person> personsWithGivenBirthYear = personList.FindAll(predicate);

            Display2(personsWithGivenBirthYear);

        }

        private void btnGetPersonWithLetter_Click(object sender, EventArgs e)

        {

            string lastInitial = txtLastNameInitial.Text.ToUpper();

                Predicate<Person> predicate = p => p.Lastname.ToUpper().StartsWith(lastInitial);

                List<Person> personWithLastInitial = personList.FindAll(predicate);

                Display2(personWithLastInitial);

        }

        private void btnDisplayAllPersons_Click(object sender, EventArgs e)

        {

            richTextBox1.Clear();

            Display2(personList);

        }

    }

}

///Lab: (due Thursday 1/15)

///Add more person object to the personList

///Add button to get / display all the people born in a given year

///(get the year from the user)

///Add button to get / display all the people whose last name start with a given letter (read from user).