Why does this violate the type constraint?

Question

I'm trying to customise ASP.NET Identity 3 so that it uses integer keys:

public class ApplicationUserLogin : IdentityUserLogin<int> { } public class ApplicationUserRole : IdentityUserRole<int> { } public class ApplicationUserClaim : IdentityUserClaim<int> { }  public sealed class ApplicationRole : IdentityRole<int> {   public ApplicationRole() { }   public ApplicationRole(string name) { Name = name; } }  public class ApplicationUserStore : UserStore<ApplicationUser, ApplicationRole, ApplicationDbContext, int> {   public ApplicationUserStore(ApplicationDbContext context) : base(context) { } }  public class ApplicationRoleStore : RoleStore<ApplicationRole, ApplicationDbContext, int> {   public ApplicationRoleStore(ApplicationDbContext context) : base(context) { } }  public class ApplicationUser : IdentityUser<int> { }  public sealed class ApplicationDbContext : IdentityDbContext<ApplicationUser, ApplicationRole, int> {   private static bool _created;    public ApplicationDbContext()   {     // Create the database and schema if it doesn't exist     if (!_created) {       Database.AsRelational().Create();       Database.AsRelational().CreateTables();       _created = true;     }   } } 

This compiles okay, but then throws a runtime error:

System.TypeLoadException

GenericArguments[0], 'TeacherPlanner.Models.ApplicationUser', on 'Microsoft.AspNet.Identity.EntityFramework.UserStore`4[TUser,TRole,TContext,TKey]' violates the constraint of type parameter 'TUser'.

The signature for UserStore is:

public class UserStore<TUser, TRole, TContext, TKey> where TUser : Microsoft.AspNet.Identity.EntityFramework.IdentityUser<TKey> where TRole : Microsoft.AspNet.Identity.EntityFramework.IdentityRole<TKey> where TContext : Microsoft.Data.Entity.DbContext where TKey : System.IEquatable<TKey> 

ApplicationUser is precisely an IdentityUser<int>. Isn't this what it's looking for?

Answer 1

Ran into this problem. It was crashing on the startup.cs file. changed

services.AddIdentity<ApplicationUser, ApplicationIdentityRole>()                 .AddEntityFrameworkStores<ApplicationDbContext>()                 .AddDefaultTokenProviders(); 

to

services.AddIdentity<ApplicationUser, ApplicationIdentityRole>()                 .AddEntityFrameworkStores<ApplicationDbContext,int>()                 .AddDefaultTokenProviders(); 

declaring the key type seemed to get past the crash