UserManager.AddToRole passes null user id to FindByIdAsync

Question

I have a MVC web site that uses custom identity with my own tables. Most everything is working fine... adding users, roles, etc.

Now I'm adding a user to a role through the user manager like this:

var result = um.AddToRole(userID, roleName);

the "um" is my UserStore interface. Before it calls the AddToRole method it calls the FindByIdAsync method passing in a null value for the userID. Not good. That breaks the entire process.

Microsoft Identity decides how those routines are called behind the scenes, and I can't figure out why a null is getting passed. I'm guessing that I have something wrong in part of the UserStore implementation, but I'm having trouble finding it.

What calls the FindByIdAsync method when I try to AddToRole????

Answer 1

The AddToRole method is an extension method defined as:

/// <summary>
/// Add a user to a role
/// 
/// </summary>
/// <param name="manager"/><param name="userId"/><param name="role"/>
/// <returns/>
public static IdentityResult AddToRole<TUser, TKey>(this UserManager<TUser, TKey> manager, TKey userId, string role) where TUser : class, IUser<TKey> where TKey : IEquatable<TKey>
{
  if (manager == null)
    throw new ArgumentNullException("manager");
  return AsyncHelper.RunSync<IdentityResult>((Func<Task<IdentityResult>>) (() => manager.AddToRoleAsync(userId, role)));
}

in UserManagerExtensions . As you can see it's just calling AddToRoleAsync which in turn is defined as:

 /// <summary>
    /// Add a user to a role
    /// 
    /// </summary>
    /// <param name="userId"/><param name="role"/>
    /// <returns/>
    public virtual async Task<IdentityResult> AddToRoleAsync(TKey userId, string role)
    {
      this.ThrowIfDisposed();
      IUserRoleStore<TUser, TKey> userRoleStore = this.GetUserRoleStore();
      TUser user = await TaskExtensions.WithCurrentCulture<TUser>(this.FindByIdAsync(userId));
      if ((object) user == null)
        throw new InvalidOperationException(string.Format((IFormatProvider) CultureInfo.CurrentCulture, Resources.UserIdNotFound, new object[1]
        {
          (object) userId
        }));
      IList<string> userRoles = await TaskExtensions.WithCurrentCulture<IList<string>>(userRoleStore.GetRolesAsync(user));
      IdentityResult identityResult;
      if (userRoles.Contains(role))
      {
        identityResult = new IdentityResult(new string[1]
        {
          Resources.UserAlreadyInRole
        });
      }
      else
      {
        await TaskExtensions.WithCurrentCulture(userRoleStore.AddToRoleAsync(user, role));
        identityResult = await TaskExtensions.WithCurrentCulture<IdentityResult>(this.UpdateAsync(user));
      }
      return identityResult;
    }

in UserManager . So if this call:

TUser user = await TaskExtensions.WithCurrentCulture<TUser>(this.FindByIdAsync(userId));

is passing null for userID then by looking at the call chain it could only be because you're passing in a null value for userID.

So to answer your question:

What calls the FindByIdAsync method when I try to AddToRole????

A: UserManager.AddToRoleAsync