MVC InvalidOperationException adding role to user

Question

I was following the tutorial on this page, about how to add roles to users programatically in C# MVC. However, when the code executes I get the following error:

System.InvalidOperationException was unhandled by user code
  HResult=-2146233079
  Message=UserId not found.
  Source=Microsoft.AspNet.Identity.Core
  StackTrace:
       at Microsoft.AspNet.Identity.UserManager`2.<AddToRoleAsync>d__83.MoveNext()
    --- End of stack trace from previous location where exception was thrown ---
       at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
       at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
       at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
       at Microsoft.AspNet.Identity.AsyncHelper.RunSync[TResult](Func`1 func)
       at Microsoft.AspNet.Identity.UserManagerExtensions.AddToRole[TUser,TKey](UserManager`2 manager, TKey userId, String role)
       at SchoolRegistration.Controllers.AccountController.RoleAddToUser(FormCollection collection) in c:\Users\Kyle\Documents\Visual Studio 2013\Projects\SchoolRegistration\SchoolRegistration\Controllers\AccountController.cs:line 98
       at lambda_method(Closure , ControllerBase , Object[] )
       at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters)
       at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
       at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
       at System.Web.Mvc.Async.AsyncControllerActionInvoker.ActionInvocation.InvokeSynchronousActionMethod()
       at System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState)
       at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult)
       at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
       at System.Web.Mvc.Async.AsyncResultWrapper.End[TResult](IAsyncResult asyncResult, Object tag)
       at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult)
       at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d()
       at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()
  InnerException: 

But I can't figure out what is causing this error. Any help would be appreciated.

Code:

Inside my account controller:

[HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult RoleAddToUser(FormCollection collection)
        {
            string UserName = collection["UserName"];
            string RoleName = collection["RoleName"];
            using (var context = new ApplicationDbContext()) {
            ApplicationUser user = context.Users.Where(u => u.UserName.Equals(UserName, StringComparison.CurrentCultureIgnoreCase)).FirstOrDefault();
            var user2 = new ApplicationUser() { UserName = UserName };
            var roleStore = new RoleStore<IdentityRole>(context);
            var roleManager = new RoleManager<IdentityRole>(roleStore);
            var userStore = new UserStore<ApplicationUser>(context);
            var userManager = new UserManager<ApplicationUser>(userStore);
            userManager.AddToRole(user2.Id, RoleName);
            var account = new AccountController();
            //account.UserManager.AddToRole(user.Id, RoleName);
            ViewBag.ResultMessage = "Role added successfully.";

            var list = context.Roles.OrderBy(r => r.Name).ToList().Select(rr => new SelectListItem { Value = rr.Name.ToString(), Text = rr.Name }).ToList();
            ViewBag.Roles = list;

        }
            return View("ManageUserRoles");
        }

UPDATE:

Ok so after taking everyone's suggestions I have reworked my code to look like the following:

[HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult RoleAddToUser(FormCollection collection)
        {
            string UserName = collection["UserName"];
            string RoleName = collection["RoleName"];
            using (var context = new ApplicationDbContext()) {
            ApplicationUser user = context.Users.Where(u => u.UserName.Equals(UserName, StringComparison.CurrentCultureIgnoreCase)).FirstOrDefault();
            var user2 = UserManager.FindByNameAsync(UserName);
            var roleStore = new RoleStore<IdentityRole>(context);
            var roleManager = new RoleManager<IdentityRole>(roleStore);
            var userStore = new UserStore<ApplicationUser>(context);
            var userManager = new UserManager<ApplicationUser>(userStore);
            userManager.AddToRole(user2.Id.ToString(),RoleName);
            var account = new AccountController();
            //account.UserManager.AddToRole(user.Id, RoleName);
            ViewBag.ResultMessage = "Role added successfully.";

            var list = context.Roles.OrderBy(r => r.Name).ToList().Select(rr => new SelectListItem { Value = rr.Name.ToString(), Text = rr.Name }).ToList();
            ViewBag.Roles = list;

        }
            return View("ManageUserRoles");
        }

The weird thing is, I'm getting the exact same error. However, when I hover over my parameter now, it does in fact have a valid id and not null:

I did notice the value I receive when debugging is not the same as the value in the database (this could be due to hashing security?)

DB Value: 0752a8d8-fb0e-44d9-b8b0-57ccbbff826b

UPDATE 2:

For anyone having the same problem with the ids not matching, try using the FindByName method instead of FindByNameAsync. Worked for me!

Answer 1

The error message is telling you the problem:

Message=UserId not found.

You are never setting user2.Id so when you call AddToRole it cannot find the user to add the role to because user2.Id is null.

You set user2 here: var user2 = new ApplicationUser() { UserName = UserName };

Then you reference user2.Id here but it's not been set.

userManager.AddToRole(user2.Id, RoleName);

Try finding the user by id first.