关于一个异步调用窗体的问题

Question

第1。为什么弹出的进度条窗体不是模式窗体，就是说主窗体还可以操作。怎么样才能把它变成模式窗体
--------------------
try:
Form2 ft= new Form2();
ft.Show(this); 
2、
private Form2 ft;
private void LoadFrm()
{
ft= new Form2();
ft.Show(this);
} 
private void btnSave_Click(object sender, System.EventArgs e)
{
  ....
 ft.Close();
}

Answer 1

private  void  btnSave_Click(object  sender,  System.EventArgs  e)  
                       {  
                                  
                                   UserInfoMode  us=  new  UserInfoMode();  
                                   Thread  th  =  us.StartFrm();  
                         
                                   string  v=null;  
 
                                   for  (int  i=0  ;i<10000000;i++)  
                                   {  
 
                                               v=i.ToString();  
                                   }  
 
                         
                                   MessageBox.Show("测试完成！","系统提示",MessageBoxButtons.OK,MessageBoxIcon.Information);                                     th.Abort();
                       }  //弹出进度条窗体  
public  Thread  StartFrm()  
                       {  
                                   Thread  th  =  new  Thread(new  ThreadStart(LoadFrm));  
                                   th.Start();  
                                   return th;
 
                       }
 private  void  LoadFrm()  
                       {  
                                   Form2  ft=  new  Form2();  
                                   ft.ShowDialog(this);  
                       }