C# r被接受，因为它对实际发生的事情提供了深入的解释。如果你能把你的评论放在一起作为“答案”，我会把它标记为接受。谢谢 An unhandled exception occurred while processing the request. ObjectD

r被接受，因为它对实际发生的事情提供了深入的解释。如果你能把你的评论放在一起作为“答案”，我会把它标记为接受。谢谢

An unhandled exception occurred while processing the request.

ObjectDisposedException: Cannot access a disposed object.
Object name: 'TestDb'.
Microsoft.Data.Entity.DbContext.get_ServiceProvider()

    private readonly UserManager<ApplicationUser> userManager;

    // controller's constructor
    public AuthController(UserManager<ApplicationUser> userManager) {
        this.userManager = userManager;
    }

    [AllowAnonymous, HttpPost]
    public async Task<ActionResult> ForgotPass(ForgotPassViewModel model) {
        //model checks

        var user = new UserQuery(db).GetUserByUserName(model.UserName);

        //check if user exists

        var token = await userManager.GeneratePasswordResetTokenAsync(user);
        var url = $"{config.Url}/auth/resetpass?user={user.Id}&token={WebUtility.UrlEncode(token)}";

        // send email with the reset url

        model.Success = "An email has been sent to your email address";
        return View(model);
    }

    [AllowAnonymous, HttpPost]
    public async Task<ActionResult> ResetPass(ResetPassViewModel model) {
        //model checks

        var user = new UserQuery(db).GetUserById(model.UserId);

        //error occurs here:
        var result = await userManager.ResetPasswordAsync(user, model.Token, model.Password);

        //check result

        model.Success = "Password successfully reset";
        return View(model);
    }

    public ApplicationUser GetUserByUserName(string userName) {
        using (var db = this.dbContext) {
            var user = (from u in db.Users
                        where u.UserName == userName
                        select u).SingleOrDefault();
            return user;
        }
    }

var user = await userManager.FindByEmailAsync(model.UserName);

var user = await userManager.FindByIdAsync(model.UserId);

DbContext context = null;
try 
{
    context = new DbContext();
    ...stuff inside the using block ...
}
finally 
{
    if(context!=null)
        context.Dispose()
}

using(DbContext context = new DbContext()) 
{
    ...stuff inside the using block ...
}

services.AddTransient<Func<MyDbContext>>( (provider) => new Func<MyDbContext>( () => new MyDbContext()));

public class MyService 
{
    public readonly Func<MyDbContext> createMyContext;

    public MyService(Func<MyDbContext> contextFactory)
    {
        this.createContext = contextFactory;
    }

    public User GetUserById(Guid userId) 
    {
        // note we're calling the delegate here which 
        // creates a new instance every time
        using(var context = createContext()) 
        {
            return context.User.FirstOrDefault(u => u.Id = userId);
        }
    }
}