无法跟踪实体类型“IdentityUser”的实例，因为已跟踪另一个具有与 {'Id'} 相同键值的实例

Question

I am using as.net core Identity to handle users, I am trying to update the password with the method ResetPasswordAsync() but I get the error message

The instance of entity type 'CustomUser' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked.

CustomUser being a class that inherit from IdentityUser

The reason of this error is probably because I am querying for the user before I update it, but I don't know what the problem is since I am using AsNoTracking(). So I believe the problem might be something more related to the IdentityUser class.

here is the code:

public async Task<bool> UpdatePassword(int userId, string token, string password)
{
     var user = await _context.Users.AsNoTracking().FirstOrDefaultAsync(x => x.Id == userId);
     var results = await _userManager.ResetPasswordAsync(user, token, password);
     return true;
}

code that is called before this one:

public async Task<bool> SendForgetPasswordEmail(string username) {
    var user = await _context.Users.AsNoTracking().FirstOrDefaultAsync(x => x.UserName == userName);
    var token = await _userManager.GeneratePasswordResetTokenAsync(user);
    var mailServiceVars = _configuration.GetSection("MailService");
    var usernameMail = mailServiceVars["Username"];
    var passwordMail = mailServiceVars["Password"];
    var mailService = new MailService("smtp.gmail.com", usernameMail, passwordMail);

    mailService.SendEmail(
        username,
        "Recover your Password",
        string.Concat("https://localhost:44374/resetPassword?token=", token),
        string.Empty
        );
    return true;
}

_context is a dbContext that inherits Entity's IdentityDbContext class.

_userManager is a UserManager class from AspNetCore.Identity library.

_contex, _configuration and _userManager are initialized through dependency injection.

The Users table that I am accessing with _context was created with Identity library.

please let me know if you have any more questions or if you need more. This is a simplified version of my code.

Answer 1

So it turns out I found a way to fix it. Just using _userManager instead of _context here:

     var user = await _context.Users.AsNoTracking().FirstOrDefaultAsync(x => x.Id == userId);

so instead the code would be

public async Task<bool> UpdatePassword(int userId, string token, string password)
{
     var user = await _userManager.Users.FirstOrDefaultAsync(x => x.Id == userId);
     var results = await _userManager.ResetPasswordAsync(user, token, password);
     return true;
}