AddIdentity() fails “InvalidOperationException: Scheme already exists: Identity.Application”

Question

I\'m trying to add facebook login to my .NET Core 2.1 site

I\'m following this , guide and more specific, this (for facebook login)

After have adding the lines

Answer 1

I also had the same problem.

I found out that services.AddIdentity<ApplicationUser, ApplicationRole>() in 2 places.

I removed one of them and now everything works as expected.

Answer 2

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I had the same issue, I was registering services in two different files in the same time: Startup.cs and IdentityHostingStartup.cs files.

What I did?

I sepeprated registering the services in both files as following:

IdentityHostingStartup.cs

I only registered Identity DB Context in this file:
//lets register identity db context builder.ConfigureServices((context, services) => { services.AddDbContext<IdentityDbContext>(options => options.UseSqlServer( context.Configuration.GetConnectionString("IdentityDBConnection"), x => x.MigrationsAssembly("WebApplication1") ) );

Startup.cs

In this file I registered DefaultIdentity, Roles and EntityFrameworkstores
//I registered the DefaultIdentity, the Roles and the EntityFrameworkstores services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true) .AddRoles<IdentityRole>().AddEntityFrameworkStores<IdentityDbContext>();

Answer 3

This is a change from .Net Core 2.0->2.1, I guess the guide hasnt been updated.

After stumbling upon this SO post I : Removed the lines entire services.AddIdentity()...call (all 3 lines) (but of course kept the AddDefaultIdentity()-call that was there before

Changed back in ApplicationDbContext.cs from

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>

to

public class ApplicationDbContext : IdentityDbContext<IdentityUser>

... So if your starting out from scratch (new .Net Core 2.1-template), all you have to do is add lines

     services.AddAuthentication().AddFacebook(facebookOptions =>
        {
            facebookOptions.AppId = Configuration["...FacebookLogin:AppId"];
            facebookOptions.AppSecret = Configuration["...FacebookLogin:ClientSecret"];
        });

from the tutorial.

At least this "fix" takes me through so far that the users can register, havent investigated where my "ApplicationUser" went (in case/when I want to add more user-properties)...since there is no reference to it anymore

Answer 4

In my case, problem was after add:

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

confliting with below code, in Startup.cs:

services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("MyConnectionString")));
services.AddDefaultIdentity<IdentityUser>()
.AddEntityFrameworkStores<ApplicationDbContext>();

Answer 5

For me (ASP.NET Core v2), I had:

services.AddIdentity<MyUser, MyRole>()
                    .AddEntityFrameworkStores<ApplicationDbContext>()
                    .AddUserStore<MyUserStore>()
                    .AddRoleStore<MyRoleStore>()
                    .AddRoleManager<MyRoleManager>()
                    .AddDefaultTokenProviders();

in Startup.cs. And when I scaffolded Identity, it added IdentityHostingStartup.cs, and I had copy/pasted another similar but default block in based on some email sending code:

builder.ConfigureServices((context, services) =>
                {
                    services.AddDefaultIdentity<IdentityUser>(config =>
                    {
                        config.SignIn.RequireConfirmedEmail = false;//TODO:
                    })
                    .AddEntityFrameworkStores<ApplicationDbContext>();
                });

So I moved ALL Identity config into IdentityHostingStartup.cs (ie only 1 configure!!!) it worked as expected...

Answer 6

I had a similar issue. This might be more helpful for people using .Net Core 3.0. After digging around I found out that once you create an "Identity" area using scaffolding. A file called "IdentityHostingStartup.cs" is created inside the Identity folder.

Inside the class, another instance of "AddDefaultIdentity" is created along with a few other services.

If you remove the "addDefaultIdentity" from your "Startup.cs" your app should start. Also, If you are getting a null connection string error. Update the connection string inside of the IdentityHostintgStartup.cs

Note: Deleting either of the addDefaultIdentities will work. You just can't have it in both locations.

Hope this helps.