private void button1_Click(object sender, EventArgs e)
        {


            c1 = bylProbar.Position;
            btnStart.Enabled = false;
            btnClose.Enabled = false;

            //控制进度条速度
            timer1.Interval = 600;
            timer1.Start();
        }     
 private void timer1_Tick(object sender, EventArgs e)
        {


            if (c1 == bylProbar.PositionMax)
            {
                p1 = 0;


                timer1.Stop();
                bylProbar.Text = "完成!";
                btnClose.Enabled = true;

            }
            else
            {
                if (c1 == bylProbar.PositionMin)
                {
                    p1 = 1;

                }
                else if (c1 == 2)
                {
                    Thread t1 = new Thread(new ThreadStart(ThreadDBImportForums));
                    t1.Start();
                }
                else if (c1 == 5)
                {
                    Thread t2 = new Thread(new ThreadStart(ThreadDBTranfer));
                    t2.Start();
                }
                else if (c1 == 9)
                {
                    Thread cha = new Thread(new ThreadStart(ThreadDBImportBlog));
                    cha.Start();
                }
            }

            c1 += p1;
            Application.DoEvents();
            bylProbar.Text = c1.ToString() + " %";
            bylProbar.Position = c1;

            if (rows > 0) timer1.Interval = 20;

        }

     private void Form1_Load(object sender, EventArgs e)
        {
            bylProbar.Text = "";
            bylProbar.Position = 0;
            
        }

------解决方案--------------------

                    int b = 总数
                   int b1 = b;
                   progressBar1.Maximum = b1;
                   while (b > 0)
                   {
                       b = b - 1;
                      获取文件一条
                       int b2 = b + 1;


                       progressBar1.Value = b1 / b2;
                   }