Is it posible to add additional QueryParameters when using Authentication.Challenge [Question]

When using MSAL.js I am able to send additional query string parameters to the identity provider using extraQueryParameters when calling loginRedirect. I now need to do this in the context of an ASP.NET MVC application and cannot work out how to add extra query string parameters to the url used when creating the challenge.

If I cannot add the extra param the AzureB2C tenant that I am required to use will not accept the request and fails. Likely the provider here could/should fix this but we’ve been able to make this work for our SPA applications and it’s frustrating me not to find a solution for a webApp

Current code:

var extraParams = new Dictionary<string, string>{{"customParam", "value"}};
var authProps = new AuthenticationProperties(extraParams) { RedirectUri = "/" };
HttpContext.GetOwinContext().Authentication.Challenge(authProps);

It looks like the extraParams are getting encoded up in the state rather than adding extra parameters to the query string

[gavinbarron]

Thanks so much for this, it was exactly what we needed to unblock us 😃

[jmprieur]

Closing as I believe this is answered. Feel free to reopen if you disagree, @gavinbarron