// This is to show result on click on search button
 protected void Button_Search(object sender, EventArgs e)
{
    fillresult();
    DataList1.Visible = true;
}
// This is for Query String
 Page Load ()
{
  Fill_result_using_query_string();
  DataList1.Visible = true;
}

Invalid postback or callback argument. Event validation is enabled using '<pages
    enableEventValidation=“true”/>'