How to Redirect Users to an ASP.NET page when not Authorized?

Question

I need my users are redirected to AuthError.aspx page (\"You don\'t have the access to this page\") in the case when they are authenticated but try to access the page that t

Answer 1

On the Page_Load of your login page, you'll want to check if the user is authenticated, and if they are to redirect them to your access denied page:

protected void Page_Load(object sender, EventArgs e)
{
    if (User.Identity.IsAuthenticated) // if the user is already logged in
    {
            Response.Redirect("~/AccessDenied.aspx");
    }
}

If you want to get a little fancier, you can check the ReturnUrl parameter to determine if the user came to the page directly (such as through a bookmark they saved right to the login page) and handle that differently. Here's an example:

protected void Page_Load(object sender, EventArgs e)
    {
        if (User.Identity.IsAuthenticated)
        {

            // if they came to the page directly, ReturnUrl will be null.
            if (String.IsNullOrEmpty(Request["ReturnUrl"]))
            {
                 /* in that case, instead of redirecting, I hide the login 
                    controls and instead display a message saying that are 
                    already logged in. */
            }
            else
            {
            Response.Redirect("~/AccessDenied.aspx");
            }
        }
    }