title: Avoid page refresh
body: <p>I have to avoid page refresh. Every time I click the submit button, page is refreshed. How do I avoid that?</p>
  
  <pre><code>protected void Button1_Click(object sender, EventArgs e)
  {
      string firstname = DropDownList1.SelectedItem.Text;
  
      if (firstname == "All")
      {
          da = new SqlDataAdapter(query, con);
      }
  
      dt = new DataTable();
      dt = ds.DataTable1;
      da.Fill(dt);
      rdc.Load(Server.MapPath("CrystalReport.rpt"));
      rdc.SetDataSource(ds);
      CrystalReportViewer1.ReportSource = rdc;
      CrystalReportViewer1.RefreshReport();
  }
  </code></pre>