ASP.NET Core Identity: No service for role manager

Question

I have an ASP.NET Core app that uses Identity. It works, but when I am trying to add custom roles to the database I run into problems.

In Startup ConfigureServices I have added Identity and the role manager as a scoped service like this:

services.AddIdentity<Entities.DB.User, IdentityRole<int>>()
                .AddEntityFrameworkStores<MyDBContext, int>();

services.AddScoped<RoleManager<IdentityRole>>();

and in Startup Configure I inject RoleManager and pass it to my custom class RolesData:

    public void Configure(
        IApplicationBuilder app, 
        IHostingEnvironment env, 
        ILoggerFactory loggerFactory,
        RoleManager<IdentityRole> roleManager
    )
    {

    app.UseIdentity();
    RolesData.SeedRoles(roleManager).Wait();
    app.UseMvc();

This is the RolesData class:

public static class RolesData
{

    private static readonly string[] roles = new[] {
        "role1",
        "role2",
        "role3"
    };

    public static async Task SeedRoles(RoleManager<IdentityRole> roleManager)
    {

        foreach (var role in roles)
        {

            if (!await roleManager.RoleExistsAsync(role))
            {
                var create = await roleManager.CreateAsync(new IdentityRole(role));

                if (!create.Succeeded)
                {

                    throw new Exception("Failed to create role");

                }
            }

        }

    }

}

The app builds without errors, but when trying to access it I get the following error:

Unable to resolve service for type 'Microsoft.AspNetCore.Identity.IRoleStore`1[Microsoft.AspNetCore.Identity.EntityFrameworkCore.IdentityRole]' while attempting to activate 'Microsoft.AspNetCore.Identity.RoleManager

What am I doing wrong? My gut says there's something wrong with how I add the RoleManager as a service.

PS: I have used "No authentication" when creating the project to learn Identity from scratch.

Solution 1

What am I doing wrong? My gut says there's something wrong with how I add the RoleManager as a service.

The registration part is actually fine, tho' you should remove services.AddScoped<RoleManager<IdentityRole>>(), as the role manager is already added for you by services.AddIdentity().

Your issue is most likely caused by a generic type mismatch: while you call services.AddIdentity() with IdentityRole<int>, you try to resolve RoleManager with IdentityRole, which is an equivalent of IdentityRole<string> (string being the default key type in ASP.NET Core Identity).

Update your Configure method to take a RoleManager<IdentityRole<int>> parameter and it should work.

Solution 2

I was having this issue

No service for type 'Microsoft.AspNetCore.Identity.RoleManager`

And this page was the first result on Google. It did not answer my question, so I thought I would put my solution here, for anyone else that may be having this problem.

ASP.NET Core 2.2

The missing line for me was .AddRoles() in the Startup.cs file.

        services.AddDefaultIdentity<IdentityUser>()
            .AddRoles<IdentityRole>()
            .AddDefaultUI(UIFramework.Bootstrap4)
            .AddEntityFrameworkStores<ApplicationDbContext>();

Hope this helps someone

Source: https://docs.microsoft.com/en-us/aspnet/core/security/authorization/roles?view=aspnetcore-2.2 (at the bottom)

Comments

[RussHooker]

This was a great fix and very helpful. I also recommend calling the SeedRoles from a DatabaseInitializer so that does the CreateUsers and the roles async from the startup something likecode public async Task SeedAsync(){ await CreateUsersAsync(); await RolesData.SeedRoles(_roleManager);}

[Carlos Garcia]

And what about the UserManager?

[Eric K]

This method produced errors for me. I changed the IdentityRole<Guid> to IdentityRole throughout and it worked like a charm.

[Dave ت Maher]

I was building an internal app for a company, so I'm using active directory to authorize the user and get the roles

[Minasie Shibeshi]

I had a function where I seed some data, including roles. And when I fetched the RoleManager service, I did serviceProvider.GetRequiredService<RoleManager<IdentityRole>‌​>(); it should have been serviceProvider.GetRequiredService<RoleManager<IdentityRole<‌​int>>>(); with the generic integer specificity