LinkButton在IE8下打不开文档解决思路

LinkButton在IE8下打不开文档
private void LinkButton1_Click(object sender, System.EventArgs e)
{


  LinkButton1.Text=C.doc；
  string url_str = "~/AA/" + LinkButton1.Text;
  Response.Redirect(url_str);

   
  }



但是LinkButton在IE8下打不开文档C.doc


------解决方案--------------------------------------------------------
string url_str = "~/AA/" + C.doc;
Response.Redirect(url_str);