Move items from one listbox to other in windows

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

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

        private void Form1_Load(object sender, EventArgs e)
        {
            listBox1.Items.Add("Raj");
            listBox1.Items.Add("Ravi");
            listBox1.Items.Add("Rahul");
            listBox1.Items.Add("Raju");
            listBox1.Items.Add("Rohit");
            listBox1.Items.Add("Rajesh");
        }

        private void button1_Click(object sender, EventArgs e)
        {
          
            listBox2.Items.Add(listBox1.SelectedItem);
            int i = 0;
            i = listBox1.SelectedIndex;
            listBox1.Items.RemoveAt(i);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            listBox1.Items.Add(listBox2.SelectedItem);
            int i = 0;
            i = listBox2.SelectedIndex;
            listBox2.Items.RemoveAt(i);

        }

        private void button3_Click(object sender, EventArgs e)
        {
            int j = 0;
            for (j = 0; j <= listBox1.Items.Count - 1; j++)
            {
                listBox2.Items.Add(listBox1.Items[j]);
            }
            listBox1.Items.Clear();
        }

        private void button4_Click(object sender, EventArgs e)
        {
           
            int j = 0;
            for (j = 0; j <= listBox2.Items.Count - 1; j++)
            {
                listBox1.Items.Add(listBox2.Items[j]);
            }
            listBox2.Items.Clear();
        }
    }
}