ผมอยากได้แบบในรูปอะครับ กดปุ่ม button1 แล้วไม่สามารถกดซํ้าได้อีก ต้องรอ progressbar1 รันเสร็จก่อน แล้วค่อย กดได้อีกครั้ง

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 TestProgressBar
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            txtMin.Text = progressBar1.Minimum.ToString();
            txtMax.Text = progressBar1.Maximum.ToString();
            panel1.Visible = false;
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            btnStart.Enabled = false;
            panel1.Visible = true;
            if (radBlocks.Checked == true)
            {
                progressBar1.Style = ProgressBarStyle.Blocks;
            }
            else if (radContinuous.Checked)
            {
                progressBar1.Style = ProgressBarStyle.Continuous;
            }
            else
            {
                progressBar1.Style = ProgressBarStyle.Marquee;
            }
            progressBar1.Minimum = Convert.ToInt32(txtMin.Text);
            progressBar1.Maximum = Convert.ToInt32(txtMax.Text);

            for (int i = progressBar1.Minimum; i <= progressBar1.Maximum; i++)
            {
                progressBar1.Value = i;
                this.Text = i.ToString();
                System.Threading.Thread.Sleep(100);
            }

            btnStart.Enabled = true;
            panel1.Visible = false;
        }

    }
}