How to custom/override User.IsInRole in ASP.NET Core

For User.IsInRole, it is ClaimsPrincipal which is not registered as service, so, you could not replace ClaimsPrincipal, and you could not override IsInRole.

For a workaround, if you would not use extension method, you could try to implement your own ClaimsPrincipal and Controller.

• CustomClaimsPrincipal which is inherited from ClaimsPrincipal

  public class CustomClaimsPrincipal: ClaimsPrincipal
  {
  
  public CustomClaimsPrincipal(IPrincipal principal):base(principal)
  {
  
  }
  
  public override bool IsInRole(string role)
  {
      return base.IsInRole(role);
  }
  }
  

• ControllerBase to change ClaimsPrincipal User to CustomClaimsPrincipal User

  public class ControllerBase: Controller
  {
      public new CustomClaimsPrincipal User => new CustomClaimsPrincipal(base.User);
  }
  

• Change the Controller from inheriting ControllerBase.

  public class HomeController : ControllerBase
  {
         public IActionResult About()
  {
      ViewData["Message"] = "Your application description page.";
      var result = User.IsInRole("Admin");
  
      return View();
  }
  

• Change the logic in public override bool IsInRole(string role) based on your requirement