System.ArgumentNullException:Value cannot be null

Question

Hi Team I am facing this issue on my IdentityConfig.cs using asp.net mvc to build user login registration. How do i fix this issue? Please assist me, thanks. public class ApplicationSignInManager : SignInManager string > { public ApplicationSignInManager(ApplicationUserManager userManager, IAuthenticationManager authenticationManager) : base (userManager, authenticationManager) // System exception here. { } public override Task CreateUserIdentityAsync(ApplicationUser user) { return user.GenerateUserIdentityAsync((ApplicationUserManager)UserManager); } public static ApplicationSignInManager Create(IdentityFactoryOptions options, IOwinContext context) { return new ApplicationSignInManager(context.GetUserManager(), context.Authentication); } }

Guest User · Answer

Hi Swamy will inbox you IP address for my AnyDesk

Viswanatha Swamy · Answer

Is there a way you can do screen share? we can hunt the issue down.

Guest User · Answer

Hi Swamy After debugging i found out the following error and when adding it to watch.

Viswanatha Swamy · Answer

Hello, Could you please place a debugger inside the Application Sign In Manager and put the first parameter in to watch? Let's see whether it gives us an object OR null. Many thanks.

Guest User · Answer

Hi VIswanatha I did and called it Startup.Auth.cs file under App_Start folder and its calling the relevant namespace. using System; using Microsoft.AspNet.Identity; using Microsoft.AspNet.Identity.Owin; using Microsoft.Owin; using Microsoft.Owin.Security.Cookies; using Microsoft.Owin.Security.Google; using Owin; using eNtsaTrainingRegistration.Models; namespace eNtsaTrainingRegistration { public partial class Startup { public void ConfigureAuth(IAppBuilder app) { app.CreatePerOwinContext(ApplicationDbContext.Create); app.CreatePerOwinContext (ApplicationSignInManager.Create); app.CreatePerOwinContext (ApplicationUserManager.Create); app.CreatePerOwinContext (ApplicationRoleManager.Create); app.UseCookieAuthentication( new CookieAuthenticationOptions { AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie, LoginPath = new PathString( "/login" ), Provider = new CookieAuthenticationProvider { OnValidateIdentity = SecurityStampValidator.OnValidateIdentity ( validateInterval:TimeSpan.FromMinutes(30), regenerateIdentity:(manager, user) => user.GenerateUserIdentityAsync(manager)) } }); app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie); app.UseTwoFactorSignInCookie(DefaultAuthenticationTypes.TwoFactorCookie, TimeSpan.FromMinutes(5)); app.UseTwoFactorRememberBrowserCookie(DefaultAuthenticationTypes.TwoFactorRememberBrowserCookie); } } }

Viswanatha Swamy · Answer

When we are seeing the userManager is null. I am assuming that it is not able to load it using dependency injection. Could you please verify your Start Up class public partial class Startup { // For more information on configuring authentication, please visit http://go.microsoft.com/fwlink/?LinkId=301864 public void ConfigureAuth(IAppBuilder app) { // Configure the db context, user manager and signin manager to use a single instance per request app.CreatePerOwinContext(ApplicationDbContext.Create); app.CreatePerOwinContext(ApplicationUserManager.Create); app.CreatePerOwinContext(ApplicationSignInManager.Create); } }

Guest User · Answer

using System; using System.Collections.Generic; using System.Linq; using System.Web; using Owin; using Microsoft.Owin; [assembly:OwinStartup( typeof (eNtsaTrainingRegistration.Startup))] namespace eNtsaTrainingRegistration { public partial class Startup { public void Configuration(IAppBuilder app) { ConfigureAuth(app); } } }

Viswanatha Swamy · Answer

Good evening. Could you please verify 1. you have configured User Manager and ApplicationSignInManager inside the Startup class. public void ConfigureAuth(IAppBuilder app) { // Configure the db context, user manager and signin manager to use a single instance per request }