title: Trouble using response.redirect
body: <p>Hi and sorry for my poor english.</p>
  
  <p>I have an Asp.net + Vb.Net application and here is an example of code illustrating my problem : </p>
  
  <p>First I have Default.aspx page with 2 buttons, "Valid" and "Redirect"</p>
  
  <pre><code> Protected Sub butvalid_Click(sender As Object, e As EventArgs) Handles butvalid.Click
  
      If (File.Exists(Server.MapPath("log.txt"))) Then
          Dim lines() As String = IO.File.ReadAllLines(Server.MapPath("log.txt"))
  
          Dim tmp As Integer = Convert.ToInt32(lines(lines.Length - 1))
          tmp = tmp + 1
  
          File.AppendAllText(Server.MapPath("log.txt"), Environment.NewLine &amp; tmp.ToString)
      Else
          File.WriteAllText(Server.MapPath("log.txt"), "1")
      End If
  
  End Sub
  
  Protected Sub Redirect_Click(sender As Object, e As EventArgs) Handles Redirect.Click
      Response.Redirect("accueil.aspx")
  End Sub
  </code></pre>
  
  <p>Valid button write into a txt file and Redirect is redirecting ...</p>
  
  <p>Here is the page_load code of accueil.aspx : </p>
  
  <pre><code>Threading.Thread.Sleep(3000)
  Response.Redirect("default.aspx")
  </code></pre>
  
  <p>The problem is when I click on Redirect button in Default.aspx page, the valid button remains accessible and user can click on Valid button.</p>
  
  <p>How can I disable Valid button after Redirect click ?</p>
  
  <p>Thanks in advance.</p>