public partial class Form2 : Form
{
 public Form2(int _Minimum,int _Maximum)//带参数，表示进度条的范围的最小值和最大值
 {
   InitializeComponent();
   progressBar1.Maximum=_Maximum;//设置范围最大值
   progressBar1.Value = progressBar1.Minimum = _Minimum;//设置范围最小值
 }
 public void setPos(int value)//设置进度条当前进度值
 {
   if (value < progressBar1.Maximum)//如果值有效
   {
     progressBar1.Value = value;//设置进度值
     label1.Text = (value * 100 / progressBar1.Maximum).ToString() + "%";//显示百分比
   }
   Application.DoEvents();//重点，必须加上，否则父子窗体都假死
 }
 private void Form2_Load(object sender, EventArgs e)
 {
   this.Owner.Enabled = false;//设置父窗体不可用
 }
 private void Form2_FormClosed(object sender, FormClosedEventArgs e)
 {
   this.Owner.Enabled = true;//回复父窗体为可用
 }
}

private void button1_Click(object sender, EventArgs e)
{
   Form2 fm = new Form2(0,100);
   fm.Show(this);//设置父窗体
   for (int i = 0; i < 100; i++)
   {
     fm.setPos(i);//设置进度条位置
     Thread.Sleep(100);//睡眠时间为100
   }
   fm.Close();//关闭窗体
}

public Form OwnerForm;
public Form2(int _Minimum,int _Maximum,Form _OwnerForm)//带参数，表示进度条的范围的最小值和最大值
{
   InitializeComponent();
   progressBar1.Maximum=_Maximum;//设置范围最大值
   progressBar1.Value = progressBar1.Minimum = _Minimum;//设置范围最小值
   this.OwnerForm=_OwnerForm;
}
private void Form2_Load(object sender, EventArgs e)
{
   this.OwnerForm.Enabled = false;//设置父窗体不可用
}
private void Form2_FormClosed(object sender, FormClosedEventArgs e)
{
   this.OwnerForm.Enabled = true;//回复父窗体为可用
}

private void button1_Click(object sender, EventArgs e)
{
   Form2 fm = new Form2(0,100,this);
   fm.Show();//设置父窗体
   for (int i = 0; i < 100; i++)
   {
     fm.setPos(i);//设置进度条位置
     Thread.Sleep(100);//睡眠时间为100
   }
   fm.Close();//关闭窗体
}