using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace testApp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            

        }
        private void button1_Click(object sender, EventArgs e)
        {
            usingIteration();
            usingComparer();
            
        }

        /// <summary>
        /// 迭代器使用Demo
        /// </summary>
        void usingIteration()
        {
            System.Text.StringBuilder sbShow = new StringBuilder();
            System.Collections.IEnumerator ie = this.comboBox1.Items.GetEnumerator();

            while (ie.MoveNext())
            {
                sbShow.AppendLine(ie.Current.ToString());
            }
            MessageBox.Show(sbShow.ToString());
            /*显
            ---line1---
            ---line5---
            ---line3---
            ---line2---
            ---line4---
            ---line7---
            ---line8---
            ---line6---
             */
        }

        /// <summary>
        /// LIST排序Demo
        /// </summary>
        void usingComparer()
        {
            StringSort sort = new StringSort();
            System.Collections.ArrayList arrList = new System.Collections.ArrayList(comboBox1.Items);
            arrList.Sort(sort);
            System.Text.StringBuilder sbShow = new StringBuilder();
            for (int i = 0; i < arrList.Count; i++)
            {
                sbShow.AppendLine(arrList[i].ToString());
            }
            MessageBox.Show(sbShow.ToString());
            /*
            ---line1---
            ---line2---
            ---line3---
            ---line4---
            ---line5---
            ---line6---
            ---line7---
            ---line8---
             */
        }
    }

    public class StringSort : System.Collections.IComparer
    {
        public int Compare(object x, object y)
        {
            string str1 = x as string;
            string str2 = y as string;
            if (str1 == null || str2 == null)
            {
                throw new Exception("Item Error!");
            }
            else
            {
                if (intGetIndex(str1) < intGetIndex(str2))
                {
                    return -1;
                }
                else
                {
                    return 0;
                }
            }
        }
        int intGetIndex(string str)
        {
            return Convert.ToInt32(str.Substring(7, 1));//---line1---
        }
    }
}