C# Contains metodunun kendi geliştirdiğim algoritma sayesindeki kullanılışı.

ContainsMetod.cs

using System;
using System.Collections;
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 manuel_contains_metodu
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        ArrayList metin_liste = new ArrayList();
        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void btn_ekle_Click(object sender, EventArgs e)
        {
            string metin = txt_metin.Text;
            metin_liste.Add(metin);

            lst_metin.Items.Add(metin);



        }
        ArrayList liste_harf = new ArrayList();

        private void aranan_Metin_TextChanged(object sender, EventArgs e)
        {
            lst_metin.Items.Clear();
            if (aranan_Metin.Text.Length == 0)
            {
                foreach (string item in metin_liste)
                {
                    lst_metin.Items.Add(item);
                }
            }
            else
            } 
            
                for (int i = 0; i < metin_liste.Count; i++)
                {
                    string metin = metin_liste[i].ToString();
                    string metin2 = "";
                    for (int j = 0; j < metin.Length; j++)
                    {
                        metin2 = metin2 + metin[j].ToString();
                        if (metin2 == aranan_Metin.Text)
                        {
                            lst_metin.Items.Add(metin_liste[i]);
                        }
                        if (metin2.Length == aranan_Metin.Text.Length)
                        {
                            metin2 = metin2.Substring(1, metin2.Length - 1);

                        }
                    }
                }
            }
        }
    }
}