title: How to get current login user's username & email address in C# Azure B2C authentication without Graph API?
body: <p>How to get current login username and also their email address? Identity provider for the account is username not email. 
  Username is not returned as claims in any of policy such as sign-in, sign-up etc.
  Custom attribute like "SpouseName" can be returned as claim for sign in where I can access by <code>((ClaimsIdentity)User.Identity).FindFirst("extension_SpouseName").Value</code>
  It's an MVC application. </p>