delphy to C#

[arrowsf1]

i:=cbb1.itemindex;
j:=cbb2.itemindex;
mm1.lines.string[i]:=inttostr(j);

как правильно будет на C#

[rUs_LAN]

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

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Random rnd = new Random();
            for (int i = 0; i < 50; i++)
            {
                comboBox1.Items.Add(rnd.Next(0, 100));
                comboBox2.Items.Add(rnd.Next(0, 100));
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            int i = comboBox1.SelectedIndex;
            int j = comboBox2.SelectedIndex;
            for (int k = 0; k < i; k++)
            {
                listBox1.Items.Add("");
                
            }
            listBox1.Items.Add(j); 
        }
    }
}

nado 1 knopky 2 combo 1 listbox