Question

I have a simple ASP.Net login page. When the login button is clicked, the page should post back and the even should be handled by my server-side event handler. Instead, the page simply reloads. Page.IsPostBack is false.

I’ve put breakpoints in the Page_Load/Init (where applicable) handlers of the Master page, the ASPX page and the UserControl (ascx). When I hit the Login button, instead of getting a post back and having my event handler called, I simply get the page load as if it was a fresh request.

But that’s not the end of it! The login page takes a single query string parameter: Login.aspx?id=123456. The above failure occurs when using this parameter. However, if I enable URL Rewriting in order to make the query Login/123456, the error does not occur; I get a post back and my event handler is called in this instance.

So why am I not getting the expected behaviour from my page? What about the rewritten URL is making the problem go away?

Login Button is declared in LoginUserControl.ascx:

<asp:Button ID="SubmitLinkButton" runat="server" Text='Log In' OnClick="SubmitLinkButton_Click"></asp:Button>

And the handler in the code behind:

protected void SubmitLinkButton_Click(object sender, EventArgs e)
{
    Authenticate();
}

SubmitLinkButton_Click is never called. 🙁

Edit (more code):

//Page_Init on the Master page
protected void Page_Init(object sender, EventArgs e)
{

    if (HttpContext.Current.User.Identity.IsAuthenticated) 
    {
        try
        {

            if (SessionFacade.User != null)
            {
                loginlabel.Text = "Logged in |";
                LoginLink.Visible = true;
            }
        }
        catch
        {
            FormsAuthentication.SignOut();
            CacheFacade.RemoveSessionValues();
            Session.Abandon();
            Session.RemoveAll();
            HttpContext.Current.Response.Redirect("~/Login.aspx");
        }
    }
    else
    {
        loginlabel.Text = "";
        LoginLink.Visible = false;
    }
}

Page_Load on the ASPX page:

protected void Page_Load(object sender, EventArgs e)
{
    if (this.IsPostBack.Equals(false))
    {
        /* Some business stuff that boils down to this: */
        Session["company"] = Request["company"];
    }
}

Page_Load on the Login Control:

protected void Page_Load(object sender, EventArgs e)
{

    if (!Page.IsPostBack)
    {
        //honestly, there's no code here
    }

}

P.S: I need to keep the non-url-rewrite way of accessing the login page, because many users are still navigating to that URL.

P.P.S: Even if URL rewriting isn’t enabled, the error still occurs.

Answer 1

Whenever I’ve seen this problem in the past it has usually been attributed to URL re-writing. I would usually reach for Fiddler to trace the HTTP activity. My hunch tells me after you click the button and see the POST request it will quickly be followed up by a 302 redirect to the login page.

You note that “The above failure occurs when using this parameter” of the login.aspx page. Are you certain there is no url-rewriter configuration that for example, may strip out any querystring values and do a redirect?