protected void Button1_Click(object sender, EventArgs e) 
{ 
Label1.Text = TextBox1.Text; 

//在这做第一件事情 
dowork(); 

//做完后马上启动线程 
System.Threading.Thread thread = new System.Threading.Thread(new System.Threading.ThreadStart(ThreadChild)); 
thread.Start(); 
} 

public void ThreadChild()

{

Label2.Text = DateTime.Now.ToString();

//Response.Write("");

//响应http必然报错

//Response.Write("<script>window.open('login.aspx','','');</script>");

//通过注册即可打开窗口

Page.RegisterStartupScript("", "<script>window.open('login.aspx','','');</script>");

}