Question

What I am trying to do is basically be able to type in to the web address mysite/username and it will redirect them to there page (mysite/Profle/Default.aspx?username=username) according to there username.

Answer 1

I think this might call for more than URL rewriting.

Since there is no real difference (distinguishable by a urlrewrite regex) between mysite/username and mysite/directory, you may need to do something more like this.

In your global.asax, override the BeginRequest function. Check if the request path matches a known user name. If it does, redirect. If it does not, let the request continue naturally. Beware that this could give you trouble if you have a user name that matches a directory in your site. Also, it does expose a way (albeit time-consuming) for a malicious user to find out user names for your site by learning which names redirect to the login page.

    protected void Application_BeginRequest(object sender, EventArgs e)
    {
        var url = HttpContext.Current.Request.RawUrl;

        IEnumerable<string> userNames = GetKnownUserNames(); //Get known user names from your repository

        if (userNames.Contains(url))
        {
            Response.Redirect(String.Format("mysite/Profle/Default.aspx?username={0}", url));
        }
    }

You may have to do some tweaking to get the comparisons working just right, but this will do it.