getting Error while ef core seeding the data - asp.net-core

Question

Below is my seed class..
public static class DataInitializer
{
public static async void SeedRolesAsync(RoleManager<Role> roleManager)
{
if (roleManager.RoleExistsAsync("Administrator").Result)
return;
var role = new Role
{
Name = "Administrator",
Description = "Perform all the operations."
};
await roleManager.CreateAsync(role);
}
public static async void SeedRoleClaimsAsync(RoleManager<Role> roleManager)
{
var role = await roleManager.FindByNameAsync("Administrator");
var roleClaims = await roleManager.GetClaimsAsync(role);
foreach (var claimString in AllClaims.GetList())
{
var newClaim = new Claim(claimString, "");
if (!roleClaims.Any(rc => rc.Type.ToString() == claimString))
{
await roleManager.AddClaimAsync(role, newClaim);
}
}
}
public static async void SeedUsersAsync(UserManager<User> userManager)
{
var user = new User
{
UserName = "admin#example.com",
Email = "admin#example.com",
FirstName = "Admin",
LastName = "User",
Enabled = true
};
var result = await userManager.CreateAsync(user, "Admin#123");
if (result.Succeeded)
{
await userManager.AddToRoleAsync(user, "Administrator");
}
}
public static void SeedData(UserManager<User> userManager, RoleManager<Role> roleManager)
{
SeedRolesAsync(roleManager);
SeedRoleClaimsAsync(roleManager);
SeedUsersAsync(userManager);
}
}
calling this method in startup class DataInitializer.SeedData(userManager, roleManager);
Am getting error below error while seeding.. i am using ef core 3 for postgresql.. Am getting
System.ObjectDisposedException: 'Cannot access a disposed object.
Object name: 'MyUserManager'.'

Answer 1

Try using tasks all the way - if you don't return anything to wait on chances are the code will continue with disposal even when something hasn't completed yet.
public static async Task SeedData(UserManager<User> userManager, RoleManager<Role> roleManager)
{
await SeedRolesAsync(roleManager);
await SeedRoleClaimsAsync(roleManager);
await SeedUsersAsync(userManager);
}
public static async Task SeedRolesAsync(RoleManager<Role> roleManager)
{
⋮
}
public static async Task SeedRoleClaimsAsync(RoleManager<Role> roleManager)
{
⋮
}
public static async Task SeedUsersAsync(UserManager<User> userManager)
{
⋮
}
You can also move this call into the Main method of your Program.cs because that method can be made async.
public static async Task Main(string[] args)
{
var host = CreateHostBuilder(args).Build();
using (var scope = host.Services.CreateScope())
using (var userManager = scope.ServiceProvider.GetRequiredService<UserManager<User>>())
using (var roleManager = scope.ServiceProvider.GetRequiredService<RoleManager<Role>>())
{
await DataInitializer.SeedData(userManager, roleManager).ConfigureAwait(false);
}
await host.RunAsync().ConfigureAwait(false);
}