Cannot seed database with data - asp.net-core-mvc

Question

I wrote a class to seed the database with data. When debugging it it stacks on await IdentitySeedData.EnsurePopulated(service); Probably the problem is with usermanager.createasync(). Take a look:
namespace SportStore1
{
public class Program
{
public static void Main(string[] args)
{
var Host = BuildWebHost(args);
var Scopes = Host.Services.GetRequiredService<IServiceScopeFactory>();
using (var scope = Scopes.CreateScope())
{
var service = scope.ServiceProvider;
SeedDataFunc(service);
SeedIdentityDataFunc(service);
}
Host.Run();
}
public static void SeedDataFunc(IServiceProvider service)
{
SeedData.EnsurePopulated(service);
}
public static async void SeedIdentityDataFunc(IServiceProvider service)
{
await IdentitySeedData.EnsurePopulated(service);
}
public static IWebHost BuildWebHost(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>()
.Build();
/*
public static void Main(string[] args)
{
CreateWebHostBuilder(args).Build().Run();
}
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>();
*/
}
}
namespace SportStore1.Data
{
public static class IdentitySeedData
{
public static async Task EnsurePopulated(IServiceProvider service)
{
UserManager<IdentityUser> userManager = service.GetRequiredService<UserManager<IdentityUser>>();
IConfiguration configuration = service.GetRequiredService<IConfiguration>();
ApplicationDbContext dbContext = service.GetRequiredService<ApplicationDbContext>();
if (!dbContext.Roles.Any())
{
foreach (var role in Roles)
{
dbContext.Add(role);
await dbContext.SaveChangesAsync();
}
}
if (!dbContext.Users.Any())
{
var user = new IdentityUser() { UserName = configuration["Email"], Email = configuration["Email"], EmailConfirmed = true };
await userManager.CreateAsync(user, configuration["Password"]);
}
if (!dbContext.UserRoles.Any())
{
var roleID = dbContext.Roles.Where(p => p.Name == "Administrator").FirstOrDefault().Id;
var userID = dbContext.Users.Where(p => p.Email == configuration["Email"]).FirstOrDefault().Id;
var userRole = new IdentityUserRole<string>()
{
RoleId = roleID,
UserId = userID
};
dbContext.UserRoles.Add(userRole);
await dbContext.SaveChangesAsync();
}
}
private static List<IdentityRole> Roles = new List<IdentityRole>()
{
new IdentityRole { Name = "Administrator", NormalizedName = "Administrator", ConcurrencyStamp = Guid.NewGuid().ToString() },
new IdentityRole { Name = "Manager", NormalizedName = "Manager", ConcurrencyStamp = Guid.NewGuid().ToString() },
new IdentityRole { Name = "User", NormalizedName = "User", ConcurrencyStamp = Guid.NewGuid().ToString()}
};
}
}
It stacks on await IdentitySeedData.EnsurePopulated(service) with a message System.ObjectDisposedException: 'Cannot access a disposed object.
Object name: 'UserManager`1'.' Any solution?

Answer 1

You need to await the async method. It seems you're getting stuck on the fact that Main is synchronous, but you can change that. In C# 7.2+ you can actually just have an async main:
public static async Task Main(string[] args)
In lesser versions, you'd just do:
public static void Main(string[] args) =>
MainAsync(args).GetAwaiter().GetResult();
public static async Task MainAsync(string[] args)
{
...
}
The compiler just builds that for you under the hood when you use async Main, anyways. Remember that you'll need to also do await host.RunAsync();, if you do this.
That said, this is not the method for doing database seeding any more. See the documentation.

Answer 2

You also need to use using() statement to ensure that the dbcontext is disposed as soon as it goes out of scope.
I tried your code in a brand new asp.net core 2.0 Individual User Account which uses ApplicationUser and it works well after using using block:
public static class IdentitySeedData
{
public static async Task EnsurePopulated(IServiceProvider service)
{
UserManager<ApplicationUser> userManager = service.GetRequiredService<UserManager<ApplicationUser>>();
IConfiguration configuration = service.GetRequiredService<IConfiguration>();
using (var dbContext = service.GetRequiredService<ApplicationDbContext>())
{
//ApplicationDbContext dbContext = service.GetRequiredService<ApplicationDbContext>();
if (!dbContext.Roles.Any())
{
foreach (var role in Roles)
{
dbContext.Add(role);
await dbContext.SaveChangesAsync();
}
}
if (!dbContext.Users.Any())
{
var user = new ApplicationUser() { UserName = configuration["Email"], Email = configuration["Email"], EmailConfirmed = true };
await userManager.CreateAsync(user, configuration["Password"]);
}
if (!dbContext.UserRoles.Any())
{
var roleID = dbContext.Roles.Where(p => p.Name == "Administrator").FirstOrDefault().Id;
var userID = dbContext.Users.Where(p => p.Email == configuration["Email"]).FirstOrDefault().Id;
var userRole = new IdentityUserRole<string>()
{
RoleId = roleID,
UserId = userID
};
dbContext.UserRoles.Add(userRole);
await dbContext.SaveChangesAsync();
}
}
}
private static List<IdentityRole> Roles = new List<IdentityRole>()
{
new IdentityRole { Name = "Administrator", NormalizedName = "Administrator", ConcurrencyStamp = Guid.NewGuid().ToString() },
new IdentityRole { Name = "Manager", NormalizedName = "Manager", ConcurrencyStamp = Guid.NewGuid().ToString() },
new IdentityRole { Name = "User", NormalizedName = "User", ConcurrencyStamp = Guid.NewGuid().ToString()}
};
}
Startup:
public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
services.AddIdentity<ApplicationUser, IdentityRole>()
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders();
services.AddTransient<IEmailSender, EmailSender>();
services.AddMvc();
}
Refer to Cannot access a disposed object in ASP.NET Core when injecting DbContext