alert box problem

Question

how to show the alertbox first and then log out

if (machineID.Count != 0)
            {

                checkMachineGrpState(machineID);
        else
                {
                    Response.Write("<script>alert('You are being logged out')</script>");

                   GoSignOut();
                }
    }

 private void GoSignout()
    {
        FormsAuthentication.SignOut();
        Session.Abandon();
        Response.Redirect("~/Default.aspx");
    }

here if i dont call the GosignOut function i can see the alert box but the moment i put call the signout it does not show me the alertbox and simply signs out

So i was thinking if there is a way i can see the alertbox first and then when i press OK it should call signout function in my code behind... thanks

Answer 1

use the clientclick of the server side button that calls this logout code, then return true

e.g.

<asp:Button id="button1" runat="server" OnClientClick="javascript:alert('You are being logged out');return true;" />

edit re thought what you want. try this, I have not tested with the use of session.abandon and the Signout (which may force you to the login page)

if (machineID.Count != 0)
            {

                checkMachineGrpState(machineID);
        else
                {
                   GoSignOut();
                  Page.ClientScript.RegisterStartupScript(this.GetType(), "Redirect", "<script>alert('You are being logged out');window.location.href='" + ResolveUrl("~/Default.aspx") + "';</script>");
                }
    }

 private void GoSignout()
    {
        FormsAuthentication.SignOut();
        Session.Abandon();
    }

if you need to allow the redirect to go to a page other than the login page (which is forced due to the SignOut) you can add something like the below to you web.config. I am not 100% sure you want to allow this as it would allow none authenticated users to access the page

<location path="whateverpage.aspx">
    <system.web>
      <authorization>
        <allow users="*" />
      </authorization>
    </system.web>
  </location>

Answer 2

Response.write will write stuff out to the browser and when the browser loads the page, it parse that data (render html and execute js). No further communication or feedback is presented to the server (which is where your asp.net webforms code runs) without the browser contacting the server via a GET or POST (form submission, link, ajax).

Whats happening is you are directing output to the client but then immediately calling Response.Redirect, so the client never gets your output. Instead, it is just redirecting immediately and then displays the default.aspx page.

What you could do is still do the redirect but pass some data to the client (the querystring would be a way to do this) and then the default.aspx page would know to look for that data. If that data is found, it would complete any action necessary. In your case, you want it to alert the user.

One way of doing this is by redirecting to "~/Default.aspx?alert=1". In default.aspx, on pageload, it would look to the querystring and see if the alert key is there with the value of 1. If that was the case, it'd perform your alert.