Extension Methods

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GeometryShapes
{
    public class Cylinder
    {
        public double R { get; set; }
        public double H { get; set; }

        //methods
        public double Volume()
        {
            return Math.PI * R * R * H;
        }
    }
}
//=======================================================
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using GeometryShapes; //Added to use Add Reference

namespace MyExtensions
{
    public static class MyExtensionMethods
    {
        //this method has the same effect as Extending (inheriting from)
        //the cylinder class
        //and adding the Area method
        public static double Area(this Cylinder cylinder)
        {
            double A = 2 * Math.PI * cylinder.R * cylinder.H;
            return A;
        }

         ///Add an extension method to compute the perimeter of the cylinder (2 pi r)
        ///apply it in this form.
        public static double Perimeter(this Cylinder cylinder)
        {
            //return 2 * Math.PI * _radius;
            double P = 2 * Math.PI * cylinder.R;
            return P;
        }

        //Method to count character in a string
        public static int CountCharOccurance(this String text, char ch)
        {
            int occurence = text.Count(x => x == ch);
            return occurence;
        }

        //Method to get average exclude min and max
        public static double AvgExcludeMinNMax(this List<int> list)
        {
            double avg = list.Average(x => x - list.Min() + list.Max());
            return avg;
        }
    }
}

///An extension method for the .Net string class, the method should take a parameter
///of type character and returns the number of its occurences
///Add GUI to test this method (Enter a string, enter a character, call the extension method,
///Display result.
///
///An extension method for the .Net List class, the method is to return the average value of
///all the values excluding min and max values.
///Provide GUI to test it.

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

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;

using GeometryShapes; //Added to use reference

using MyExtensions; //Added to use reference

namespace ExtensionMethods

{

    public partial class Form1 : Form

    {

        

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

        Random rand = new Random();

        public Form1()

        {

            InitializeComponent();

        }

        private void btnVolume_Click(object sender, EventArgs e)

        {

            double r, h;

            double.TryParse(txtR.Text, out r);

            double.TryParse(txtH.Text, out h);

            Cylinder cy = new Cylinder { R = r, H = h };

            //Compute Volume

            double V = cy.Volume();

            //Display

            richTextBox1.Text = String.Format("R = {0} H = {1} \nV = {2:f3}", r, h, V);

        }

        //Compute area of a cylinder

        //To read more... http://csharp.net-tutorials.com/csharp-3.0/extension-methods/

        //To read more... http://msdn.microsoft.com/en-us/library/bb383977.aspx

        private void btnArea_Click(object sender, EventArgs e)

        {

            double r, h;

            double.TryParse(txtR.Text, out r);

            double.TryParse(txtH.Text, out h);

            Cylinder cy = new Cylinder { R = r, H = h };

            //compute area using the extended method Area

            double A = cy.Area();

            richTextBox1.Text = String.Format("R = {0} H = {1} \nV = {2:f3}", r, h, A);

        }

        private void btnPerimeter_Click(object sender, EventArgs e)

        {

            double r, h;

            double.TryParse(txtR.Text, out r);

            double.TryParse(txtH.Text, out h);

            Cylinder cy = new Cylinder { R = r, H = h };

            double p = cy.Perimeter();

            richTextBox1.Text = String.Format("R = {0} H = {1} \nP = {2:f2}", r, h, p);

        }

        private void btnCount_Click(object sender, EventArgs e)

        {

            string mainstr = txtString.Text;

            char ch = char.Parse(txtChar.Text);

                richTextBox2.Text = mainstr.CountCharOccurance(ch).ToString();

        }

        private void btnGetAvgExcludeMinNMax_Click(object sender, EventArgs e)

        {

            double avg = intList.AvgExcludeMinNMax();

            richTextBox3.Text = avg.ToString();

           

        }

        //display method to display any list

        private void Display(List<int> list)

        {

            listBox1.Items.Clear();

            foreach (int n in list)

                listBox1.Items.Add(n);

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            for (int i = 1; i <= 10; i++)

            {

                intList.Add(rand.Next(1, 12));

            }

            Display(intList);

        }

    }

}
//=====================================================

///Add an extension method to compute the perimeter of the cylinder (2 pi r)

///apply it in this form.

///

///Lab: 1/16/2015

///Add to this project: 

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

///An extension method for the .Net string class, the method should take a parameter 

///of type character and returns the number of its occurences

///Add GUI to test this method (Enter a string, enter a character, call the extension method,

///Display result.

///

///An extension method for the .Net List class, the method is to return the average value of

///all the values excluding min and max values.

///Provide GUI to test it.