请问下这句程序什么意思??setListBox3CheckState();课本上解释说是调用方法设置该复选框的状态,但我不时很明白,能不能讲详细点!!using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace CheckBoxExample
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void checkBox1_CheckedChanged(object sender, EventArgs e)
        {
            if (checkBox1.Checked && !listBox1.Items.Contains(checkBox1.Text))
            {
                listBox1.Items.Add(checkBox1.Text);
            }
            else
            {
                listBox1.Items.Remove(checkBox1.Text);
            }
        }
        private void checkBox1_Click(object sender, EventArgs e)
        {
            checkBox3.ThreeState = true;
            setListBox3CheckState();
        }