asp.net-mvc redirecting to a new page based on criteria

Question

I have code in one of my views that looks like this below where if you are logged in, it shows you the welcome notice and if you are not logged in, it shows you a link to the logon page.

    <%
        if (!Request.IsAuthenticated)
        {
    %>
    <%= Html.ActionLink("Log On", "LogOn", "Account")%>
<%
    }
        else
        {
            %>
             <img src="../images/newspic.gif" width="423" height="194"><br /><br />
<%
        }
%>

what i want is that if you are not logged in, i would like it to redirect to the login page automatically (as why have that extra step)

any suggestions on how i would go about automatically redirecting to another page from within this view above.

Answer 1

Don't reinvent the wheel. AuthorizeAttribute already does this. Just add [Authorize] above the method.

Answer 2

Your View should only be responsible for displaying your data. Your controller should handle redirection logic.

The Authorize Attribute has already been created for this purpose. Add it to your controller action method like:

public class CustomerController : Controller {

  [Authorize]
  public ActionResult Home() {
    return View("Home");
  }

}

Or alternatively it can be added to the Controller to apply to all Actions:

[Authorize]
public class CustomerController : Controller {

  public ActionResult Home() {
    return View("Home");
  }

}

Then in your web.config set something like

<authentication mode="Forms">
   <forms loginUrl="~/Login" />
</authentication>

If the user is authorized they will be shown your 'Home' view. If they are not authorized they will be redirected to '/Login'

Answer 3

This is program logic, and so it should be in the controller, not the view.

Instead of return View(); try return RedirectToAction(...); to pass to another controller/action with parameters in a nice "MVC" manner, or return Redirect(...); if you just want to use a plain url.