Using Auth0 for Asp.Net MVC project how to redirect users directly to Signup page

Question

I am implementing Auth0 for Asp.Net mvc project. I want the users to go to signup page directly upon clicking on the signup link. I see the documentation says

You can make users land directly on the Signup page instead of the Login page by specifying the screen_hint=signup parameter when redirecting to /authorize.

This is what I have in the code, how do I make sure to pass that as parameters:

        HttpContext.GetOwinContext().Authentication.Challenge(new AuthenticationProperties
        {
            RedirectUri = returnUrl ?? Url.Action("Login", "Account"),
        },
            "Auth0");

Answer 1

This resolved the issue:

var authProperties = new AuthenticationProperties();
**authProperties.Dictionary.Add("screen_hint", "signup");**
authProperties.RedirectUri = Url.Action("Login", "Account");
HttpContext.GetOwinContext().Authentication.Challenge(authProperties, "Auth0");

Now in the startup, we need to fetch the parameter supplied:

RedirectToIdentityProvider = notification =>
{
   if (notification.ProtocolMessage.RequestType == OpenIdConnectRequestType.Authentication)
    {
                // The context's ProtocolMessage can be used to pass along additional query parameters
                // to Auth0's /authorize endpoint.
                var paramsDictionary = notification.OwinContext.Request.Context.Authentication
                    .AuthenticationResponseChallenge?.Properties.Dictionary;

                **if (paramsDictionary != null && paramsDictionary.ContainsKey("screen_hint"))
                {
                    notification.ProtocolMessage.SetParameter("screen_hint",
                        paramsDictionary["screen_hint"]);
                }**
   }