求助:页面跳转问题

Note.aspx
protected void Button1_Click(object sender, EventArgs e)
{
string str = "<script language='javascript' defer>ret=window.showModalDialog('Note_Add.aspx?Action=add',window,'dialogHeight:320px;dialogWidth:600px;center:yes;Help:No;Resizable:No;Scroll:auto;Status:No;');</script>";
Response.Write(str);
}
Note_Add.aspx//当执行这个程序时就又跳出一个同样的页面,原来那个还在,这样的问题怎么解决啊?
protected void Button1_Click(object sender, EventArgs e)
{
string str_note = "insert into lab_note (note_name,note_content,note_date) values ('"+TextBox1.Text+"','"+TextBox2.Text+"','"+DateTime.Now+"')";
Comm1 co_note = new Comm1();
co_note.ENQ(str_note);
Response.Write("<script defer>alert('添加成功!');</script>");
}