Cant add AddIdentity service in NET Core web api

Question

I am using NET Core 3.1 + EntityFramework + PSQL. Trying to follow tutorials and msdn but my code doesnt work.

Here`s my startup.cs

public void ConfigureServices(IServiceCollection services)
    {            
        services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
            .AddJwtBearer(options =>
            {                
                options.TokenValidationParameters = new TokenValidationParameters
                {
                   //params
                };
            });

        services.AddIdentity<ApplicationUser, IdentityRole>()
            .AddEntityFrameworkStores<MyContext>()               
    }

Here`s my MyContext.cs

public class MyContext : IdentityDbContext<ApplicationUser> 
{        
    public DbSet<Flowers> Flowers { get; set; }
    public DbSet<Post> Posts { get; set; }

    public MyContext() : base()
    {
        Database.EnsureCreated();
    }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseNpgsql("Host=localhost...");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);          

    }
}

Here`s my ApplicationUser.cs

 public class ApplicationUser : IdentityUser
{                
    public string SpecialNumber{ get; set; }

    public ICollection<Flower> Flowers { get; set; }        
}

When i try to run app i got an exception System.AggregateException: 'Some services are not able to be constructed'

Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.ISecurityStampValidator Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.SecurityStampValidator 1[FlowersApp.Models.ApplicationUser]': Unable to resolve service for type 'FlowersApp.Models.MyContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserLogin 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserToken 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]'.) (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.ITwoFactorSecurityStampValidator Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.TwoFactorSecurityStampValidator 1[System.String]]'.) (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.ITwoFactorSecurityStampValidator Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.TwoFactorSecurityStampValidator 1[FlowersApp.Models.ApplicationUser]': Unable to resolve service for type 'FlowersApp.Models.MyContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserLogin 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserToken 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]'.) (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.IUserClaimsPrincipalFactory 1[FlowersApp.Models.ApplicationUser] Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.UserClaimsPrincipalFactory 1[FlowersApp.Models.ApplicationUser] Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.UserClaimsPrincipalFactory 2[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole]': Unable to resolve service for type 'FlowersApp.Models.MyContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserLogin 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserToken 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]'.) (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.UserManager 1[FlowersApp.Models.ApplicationUser] Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.UserManager 1[FlowersApp.Models.ApplicationUser]': Unable to resolve service for type 'FlowersApp. Models.MyContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserLogin 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserToken 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]'.) (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.SignInManager 1[FlowersApp.Models.ApplicationUser] Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.SignInManager 1[FlowersApp.Models.ApplicationUser]': Unable to resolve service for type 'FlowersApp.Models.MyContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserLogin 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserToken 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]'.) (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.RoleManager 1[Microsoft.AspNetCore.Identity.IdentityRole] Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.RoleManager 1[Microsoft.AspNetCore.Identity.IdentityRole]': Unable to resolve service for type 'FlowersApp.Models.MyContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.RoleStore 5[Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.Str ing],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]'.) (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.IUserStore 1[FlowersApp.Models.ApplicationUser] Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserLogin 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserToken 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]': Unable to resolve service for type 'FlowersApp.Models.MyContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 9[FlowersApp.Models.ApplicationUser,Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserClaim 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserLogin 1[System.String],Microsoft.AspNetCore.Identity.IdentityUserToken 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]'.) (Error while validating the service descriptor 'ServiceType: Microsoft.AspNetCore.Identity.IRoleStore 1[Microsoft.AspNetCore.Identity.IdentityRole] Lifetime: Scoped ImplementationType: Microsoft.AspNetCore.Identity.EntityFrameworkCore.RoleStore 5[Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim 1[System.String]]': Unable to resolve service for type 'FlowersApp.Models.MyContext' while attempting to activate 'Microsoft.AspNetCore.Identity.EntityFrameworkCore.RoleStore 5[Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserRole 5[Microsoft.AspNetCore.Identity.IdentityRole,FlowersApp.Models.MyContext,System.String,Microsoft.AspNetCore.Identity.IdentityUserRole 1[System.String],Microsoft.AspNetCore.Identity.IdentityRoleClaim`1[System.String]]'.)

Cant find reason of this error. Are my clases inherited right?

App runs when i delete this part of code from Startup.cs

 services.AddIdentity<ApplicationUser, IdentityRole>()
            .AddEntityFrameworkStores<MyContext>()  

Answer 1

将此添加到您的ConfigureServices的顶部您需要告诉框架它如何创建MyContext的实例（注入该服务）

 services.AddDbContext<MyContext>(options => /*<<<ADD YOUR DBCONTEXT CONFIGURATION >>>*/);

Answer 2

You forgot to write this line in your ConfigureServices section

services.AddDbContext<MyContext>(options =>
        options.UseNpgsql("your connection string"));