关于C#进度条不能充满100%的解决方案

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.Threading.Tasks;
using System.Windows.Forms;

namespace 进度条显示测试
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

    private void Form1_Load(object sender, EventArgs e)
    {
        progressBar1.Maximum = 7;
        progressBar1.Step =1;
        //Action my = Calculation;
        //this.BeginInvoke(my);
        Thread t = new Thread(Calculation);
        t.IsBackground = true;
        t.Start();

    }

    public void Calculation()
    {
        for (int i = 0; i < 7; i++)
        {
           
            double c = 1 + 3 * 2;
            Thread.Sleep(500);
            ChangeBar();
        }
        Thread.Sleep(600);
        if (this.InvokeRequired)
        {
            Action w = colosbar;
            this.Invoke(w);
        }
        else
        {
            progressBar1.Visible = false; 
        }
       
    }

    public void colosbar()
    {
        progressBar1.Visible = false;
    }

    public void ChangeBar()
    {
        if (this.InvokeRequired)
        {
            Action wt = ChangeBar;
            this.Invoke(wt);
        }
        else
        {
            if (progressBar1.Value < progressBar1.Maximum)
            {
               progressBar1.PerformStep();
                Thread.Sleep(500);
                label1.Text = "已完成" + ((double) progressBar1.Value / progressBar1.Maximum) * 100 + "%";             
               Application.DoEvents();
            }
            
          
         
        }
    }

 
}

}
进度条更新需要一定时间,所以在关闭进度条前需要让程序暂停一下大约600ms,然后在执行关闭操作…