SQLite.NET-PCL – When I check for an existing user the function always return true even if the database table is empty

So, I create an async connection on the app start which creates a "Profiles.db3" in the "data/user/0/com.your.mypackage/files" (I checked, it exists and is empty)

Everytime I try to register as a new user it always tells me there’s an existing user

This is the method to check for an existing user:

public async Task<bool> CheckExistingUser(Profile profile)
        {
            await Init();
            var d1 = db.Table<Profile>().Where(x => x.Username == profile.Username || x.Email == profile.Email).FirstOrDefaultAsync(); 
            if (d1 != null)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

And I use it when creating a new profile:

public async Task<bool> NewProfile(User profile, string picture = "user.png")
        {
            await Init();
            if ((await CheckExistingUser(profile)))
            {
                return false;
            }
            else
            {
                Profile _profile = new Profile
                {
                    Username = profile.Username,
                    Email = profile.Email,
                    Password = profile.Password,
                    Picture = picture,
                    ProfileType = ProfileType.User,
                    AdditionalData = JsonConvert.SerializeObject(new
                    {
                        profile.BorrowedBooks,
                        profile.Wishlist,
                        profile.ReturnedBooks
                    })
                };
                await db.InsertAsync(_profile);
                return true;
            }
        }

This method always returns false since CheckExistingUser returns true.

This is to initiate the connection

public async Task Init()
        {
        
            if (db != null)
                return;


                db = DependencyService.Get<ISQLiteInterface>().GetSQLiteAsyncConnection();
                await db.CreateTableAsync<Profile>();
        }
            

I call it in the SignUp view model:

 if (await _profileService.NewProfile((User)Profile))
            {
                App.Current.MainPage = new AppShell();
            }

I am new to all this stuff so I don’t see where’s the problem since the logic seems correct to me.

>Solution :

Just change your code to:

public async Task<bool> CheckExistingUser(Profile profile)
        {
            await Init();
           //use the await keyword here... otherwise you get a task object
            var d1 = await db.Table<Profile>().Where(x => x.Username == profile.Username || x.Email == profile.Email).FirstOrDefaultAsync(); 
            if (d1 != null)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

The reason is always not null is because the call returns a task.

You need to await that task instead of just checking if the task is null or not.

You see you are calling FirstOrDefaultAsync which returns a task.