Xamarin Forms- Entry, Picker etc losing its values after resuming app from background or unlocking phone

Question

I am working on a Xamarin Forms app & came across an issue where my form fields like Entry, Picker etc losing its values after resuming app from background or unlocking phone post screen timeout. I am using conventional winforms approach in my codebehind. I am not using MVVM Pattern. Please help me..

Environment is Visual Studio 2019 Community 16.6.2 with all latest packages of Xamarin Forms or Essentials etc.

Update {{CODE}}

Below is my code to set data to form fields.

 private void FillUser()
        {
            var userid = PersistentObjects.UserId;
            var user = new UserController().GetUserProfileById(userid);
            if (user != null)
            {
                TxtAadhar.Text = user.AadharNumber;
                TxtAchievements.Text = user.Achievements;


                DdlArtField.SelectedItem = ((IList<MasterItem>)DdlArtField.ItemsSource).FirstOrDefault(c => c.Id == user.ArtDomain);
                DdlLanguages.SelectedItem = ((IList<MasterItem>)DdlLanguages.ItemsSource).FirstOrDefault(c => c.Id == user.ArtLanguage);


                DdlProfession.SelectedItem = ((IList<MasterItem>)DdlProfession.ItemsSource).FirstOrDefault(c => c.Id == user.ArtProfession);
                DdlEducation.SelectedItem = ((IList<MasterItem>)DdlEducation.ItemsSource).FirstOrDefault(c => c.Id == user.QualificationId);
                TxtMobileNum.Text = user.MobileNumber;
                TxtBankAccount.Text = user.BankAccount;
                DdlBanks.SelectedItem = ((IList<MasterItem>)DdlBanks.ItemsSource).FirstOrDefault(c => c.Id == user.BankId);
                DdlBloodGroups.SelectedItem = user.BloodGroup;//((IList<MasterItem>)DdlBloodGroups.ItemsSource).FirstOrDefault(c => c.Name == user.BloodGroup);
                TxtExp.Text = user.DomainExperience.ToString();
                TxtFathersName.Text = user.FathersName;
                TxtEmail.Text = user.Email.ToLower();
                DdlGender.SelectedItem = user.Gender;
                TxtFullName.Text = user.FullName.ToTitleCase();
                TxtIfscCode.Text = user.IfscCode.ToUpper();
                TxtDob.Date = user.Dob;
                TxtAltMobile.Text = user.AltMobileNumber;
                TxtLocality.Text = user.Locality.ToTitleCase();
                DdlDistricts.SelectedItem = ((IList<MasterItem>)DdlDistricts.ItemsSource).FirstOrDefault(c => c.Id == user.DistrictId);
                TxtPO.Text = user.PostOffice.ToTitleCase();
                TxtVillage.Text = user.VillageName.ToTitleCase();
                TxtThana.Text = user.PoliceStation.ToTitleCase();
            }
        }

APP.Xaml.cs

 public partial class App : Application
    {
        /// <summary>
        /// 
        /// </summary>
        public App()
        {
            InitializeComponent();
            OneSignal.Current.SetLogLevel(LOG_LEVEL.VERBOSE, LOG_LEVEL.NONE);
            OneSignal.Current.StartInit(Constants.OSAppId).HandleNotificationOpened(NotificationOpenClicked).InFocusDisplaying(OSInFocusDisplayOption.Notification).EndInit();
            Application.Current.MainPage = new Login();

        }

        private void NotificationOpenClicked(OSNotificationOpenedResult result)
        {
            PersistentObjects.ClickedNotification = true;

        }


        /// <summary>
        /// 
        /// </summary>
        protected override void OnStart()
        {
            OneSignal.Current.RegisterForPushNotifications();
        }



    }

The form fields , having values , coming from database and is displaying in the form fields are working as expected. The form fields that are blank and needs user input are getting refreshed or emptied. I hope this will help.

If you need code of special area/operation please do let me know.

Answer 1

@BenReierson Comment helped me. It was a nasty mistake...I was calling api and filling data to form fields using FillUser() method, which is glued in OnAppearing(). Removing that from there worked!!!!

Thanks.