I've recently stumbled on this strange error. It looks like one of my object is disposing before my method finish all async Task. But let's take a look.
I have that async method which seeds my database. It's called in Startup
class in Configure
method.
private void InitDatabase(IApplicationBuilder app) {
using (var scope = app.ApplicationServices.CreateScope()) {
var services = scope.ServiceProvider;
try {
var context = services.GetRequiredService<GrabGoContext>();
new DatabaseInitializer().InitializeAsync(context,
services.GetService(typeof(UserManager<User>)) as UserManager<User>,
services.GetService(typeof(SignInManager<User>)) as SignInManager<User>,
services.GetService(typeof(RoleManager<IdentityRole<int>>)) as RoleManager<IdentityRole<int>>,
_logger).Wait();
_logger.LogDebug("Database initialization finished.");
}
catch (Exception ex) {
_logger.LogError(ex, "An error occurred while seeding the database.");
if (Debugger.IsAttached) Debugger.Break();
}
}
}
And that method from DatabaseInitializer
class:
public async Task InitializeAsync(GrabGoContext context,
UserManager<User> userManager,
SignInManager<User> signInManager,
RoleManager<IdentityRole<int>> roleManager,
ILogger<Startup> logger) {
if(IsDatabaseInialized) return;
IsDatabaseInialized = true;
await context.Database.EnsureCreatedAsync();
await AddStores(context);
await AddProducts(context);
await AddRoles(roleManager)
.ContinueWith(t => AddRolesToUsers(userManager)); // <- Here throws exception "System.ObjectDisposedException" for object `userManager`
await AddUsers(userManager);
await context.SaveChangesAsync();
}
The thing is that if I use ContinueWith
to chain Tasks, it throws System.ObjectDisposedException
on userManager
object. But I need to use ContinueWith
, because I need Roles
before I will assign users to that roles.
My methods responsible for adding roles
private async Task AddRoles(RoleManager<IdentityRole<int>> roleManager) {
if (await roleManager.Roles.AnyAsync()) return;
var roles = (List<IdentityRole<int>>) new RolesListExample().GetExamples();
foreach (var role in roles) {
var result = await roleManager.CreateAsync(role);
if(!result.Succeeded) throw new ApplicationException("Erros while adding roles: " +
JsonConvert.SerializeObject(result.Errors));
}
}
private async Task AddRolesToUsers(UserManager<User> userManager) {
var registerModels = (List<RegisterModel>)new RegisterListRequestExample().GetExamples();
foreach(var registerModel in registerModels) {
var user = await userManager.FindByEmailAsync(registerModel.Email);
var result = await userManager.AddToRoleAsync(user, registerModel.Role.ToString());
if(!result.Succeeded)
throw new ApplicationException("Erros while adding roles to user: " +
JsonConvert.SerializeObject(result.Errors));
}
}
And also my RolesListExample
class :
public class RolesListExample : IExamplesProvider {
/// <inheritdoc />
public object GetExamples() {
var roles = new List<IdentityRole<int>>();
foreach (var availableRole in (AvailableRoles[]) Enum.GetValues(typeof(AvailableRoles))) {
roles.Add(new IdentityRole<int>(availableRole.ToString()));
}
return roles;
}
}
My question is:
Why is my object disposing before all Tasks are finished?
I assume that's because of the using
. Also I found that Question , but didn't clarify situation for me.
@Update
As suggested by @PanagiotisKanavos I removed using
statement and it solved my disposing problem. Thanks!
You are awaiting only the continuation of the task. Instead of:
await AddRoles(roleManager).ContinueWith(t => AddRolesToUsers(userManager));
...try:
var task1 = AddRoles(roleManager);
var task2 = task1.ContinueWith(t => AddRolesToUsers(userManager));
await task1;
await task2;
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