Can somebody please help me? I am having trouble running the app after scaffolding Identity. It keeps showing the No service for type "’Microsoft.AspNetCore.Identity.UserManager`1[OAS.Model.User]’ has been registered." exception. I have searched thorugh the Internet and checked the _LoginPartial.cshtml as well. The @inject part is correct but it is still not working. Here are my code files:

_LoginPartial.cshtml:

@using Microsoft.AspNetCore.Identity
@using OAS.Model

@inject SignInManager<User> SignInManager
@inject UserManager<User> UserManager

<ul class="navbar-nav">
@if (SignInManager.IsSignedIn(User))
{
    <li class="nav-item">
        <a id="manage" class="nav-link text-dark" asp-area="Identity" asp-page="/Account/Manage/Index" title="Manage">Hello @UserManager.GetUserName(User)!</a>
    </li>
    <li class="nav-item">
        <form id="logoutForm" class="form-inline" asp-area="Identity" asp-page="/Account/Logout" asp-route-returnUrl="@Url.Page("/Index", new { area = "" })">
            <button id="logout" type="submit" class="nav-link btn btn-link text-dark">Logout</button>
        </form>
    </li>
}
else
{
    <li class="nav-item">
        <a class="nav-link text-dark" id="register" asp-area="Identity" asp-page="/Account/Register">Register</a>
    </li>
    <li class="nav-item">
        <a class="nav-link text-dark" id="login" asp-area="Identity" asp-page="/Account/Login">Login</a>
    </li>
}
</ul>

User.cs file:

 public class User : IdentityUser
    {
        [Required]
        public string Description { get; set; }
    }

I have no idea what to change next.

>Solution :

looks like you’re trying to use the UserManager, but it has not been registered with the service container.

try this:

services.AddIdentity<User, IdentityRole>().AddEntityFrameworkStores<ApplicationDbContext>();