CODEWITHSUNDEEP
c#xamarin.formssqlite.net
spoooooooonman
spoooooooonman

Reputation: 43

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.

Upvotes: 1

Views: 109

Answers (1)

Jonathan Alfaro
Jonathan Alfaro

Reputation: 4376

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.

Upvotes: 0

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