세우세상 -> 이전 : http://doldolcoding.tistory.com/

namespace ButtonExam
{
    public partial class Form1 : Form
    {
        ButtonExam.Pro form = new Pro();
        public ProgressBar okpro = null;
       
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            MessageBox.Show("This is Main Thread");
           
            form.Show();
            form.Text = "안녕";
        }

        private void ThreadTask()
        {
            int stp;
            int newval;
            Random rnd = new Random();
            okpro = form.getProg();
            while (true)
            {
                stp = okpro.Step * rnd.Next(-1, 2);
                newval = okpro.Value + stp;

                if (newval > okpro.Maximum)
                    newval = okpro.Maximum;
                else if (newval < okpro.Minimum)
                    newval = okpro.Minimum;

                okpro.Value = newval;

                Thread.Sleep(100);
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Thread trd = new Thread(new ThreadStart(this.ThreadTask));
         trd.IsBackground = true;
         trd.Start();
        }
    }
}

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 ButtonExam
{
    public partial class Pro : Form
    {

        public ProgressBar getProg()
        {
            return this.progressBar1;
        }

        public Pro()
        {
            InitializeComponent();
        }

    }
}