ListBox not updating on button click

Question

I recently started to learn WPF and naturally I try to understand MVVM which from what I read is the normal way to program wpf applications.

I took a basic source from the internet for user management and started to build from there. Basically I have a listbox bind to a sql database through a ObservableCollection that display the username and when an item is selected all the details for that user are show in a datagrid.

In the window I also have a groupbox where you can add a new user to database and here lies the problem: the listox is not updated with the new user after I click the add button - I need to close and reopen the application for the new user to be shown in the listbox.

Where am I wrong?

My model class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
using System.Threading.Tasks;

namespace user_management.Model
{
    public class Utilizatori:INotifyPropertyChanged
    {
        //public int id { get; set; }

        private int _id;
        public int id
        {
            get
            {
                return _id;
            }
            set
            {
                this._id = value;
                OnPropertyChanged("id");
            }
        }

        //public string nume { get; set; }
        private string _nume;
        public string nume
        {
            get
            {
                return _nume;
            }
            set
            {
                this._nume = value;
                OnPropertyChanged("nume");
            }
        }



        //public string parola { get; set; }
        private string _parola;
        public String parola
        {
            get
            {
                return _parola;
            }
            set
            {
                this._parola = value;
                OnPropertyChanged("parola");
            }
        }
        //public bool isadmin { get; set; }
        private bool _isadmin;
        public bool isadmin
        {
            get
            {
                return _isadmin;
            }
            set
            {
                this._isadmin = value;
                OnPropertyChanged("isadmin");
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = PropertyChanged;

            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }

        }






    }
}

My viewModel:

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Windows.Controls;
using System.Windows.Input;
using user_management.Model;



namespace user_management.ViewModel
{
    public class UtilizatoriViewModel : INotifyPropertyChanged, IRequireViewIdentification
    {

        private Guid _viewId;

        public Guid ViewID
        {
            get { return _viewId; }
        }

        static String connectionString = @"*****;";
        SqlConnection con;
        SqlCommand cmd;
        SqlDataAdapter adapter;
        SqlDataReader reader;
        DataSet ds;
        //public ObservableCollectionutilizatori { get; set; }
        private ObservableCollection _utilizatori;

        public ObservableCollection utilizatori
        {
            get
            {
                return _utilizatori;
            }
            set
            {
                _utilizatori = value;
                OnPropertyChanged("utilizatori");
            }
        }



        public String txtSelectedItem { get; set; }
       
        
        public UtilizatoriViewModel()
        {
            txtSelectedItem = "Va rugam sa alegeti un utilizator";
            FillList();
            _viewId = Guid.NewGuid();


        }



        

        public Utilizatori utiliz { get; set; }

        

        private string userName;
        
        public string UserName
        {
            get { return this.userName; }
            set
            {
               
                    this.userName = value;
                    this.OnPropertyChanged("UserName");

               
            }
        }



        private string numeNou;

        public string NumeNou
        {
            get { return this.numeNou; }
            set
            {

                this.numeNou = value;
                this.OnPropertyChanged("NumeNou");


            }
        }

        private string parolaNou;

        public string ParolaNou
        {
            get { return this.parolaNou; }
            set
            {

                this.parolaNou = value;
                this.OnPropertyChanged("ParolaNou");


            }
        }

        private bool eadminNou; 

        public bool EadminNou
        {
            get { return this.eadminNou; }
            set
            {

                if (eadminNou == value) return;

                eadminNou = value;

                this.OnPropertyChanged(EadminNou.ToString());
            }
        }


        public string Password { private get; set; }


        private ICommand _login;

        public ICommand Login
        {
            get
            {
                if (_login == null)
                {
                    _login = new RelayCommand(
                        param => Logare()
                    );
                }
                return _login;
            }
        }

        //private bool CanSave()
        //{
        //   return true;
        //}


        private ICommand _iesire;

        public ICommand Iesire
        {
            get
            {
                if (_iesire == null)
                {
                    _iesire = new RelayCommand(
                        param => IesireW()
                    );
                }
                return _iesire;
            }
        }


        private ICommand _salveaza;
        public ICommand Salveaza
        {
            get
            {
                if (_salveaza == null)
                {
                    _salveaza = new RelayCommand(
                        param => AdaugaP()
                    );
                }
                return _salveaza;
            }
        }



        private ICommand _salveazaModificari;
        public ICommand SalveazaModificari
        {
            get
            {
                if (_salveazaModificari == null)
                {
                    _salveazaModificari = new RelayCommand(
                        param => ModificaUser()
                    );
                }
                return _salveazaModificari;
            }
        }


        private void Logare()
        {
            {
                String message = "Login failed. please try again.";
                try
                {
                    con = new SqlConnection(connectionString);
                    con.Open();
                    cmd = new SqlCommand("Select * from dbo.Users where UsernAME=@UserName", con);
                    cmd.Parameters.AddWithValue("@UserName", UserName);
                    
                    reader = cmd.ExecuteReader();
                    if (reader.Read())
                    {
                        if (reader["uSERpASS"].ToString().Equals(Password, StringComparison.InvariantCulture))
                        {
                           Utilizatori logati = new Utilizatori();
                            message = "1";
                            //logati.nume  = txtUserId.Text.ToString();
                            logati.nume = reader["UsernAME"].ToString();
                            logati.parola = reader["uSERpASS"].ToString();
                        }
                    }

                    reader.Close();
                    reader.Dispose();
                    cmd.Dispose();
                    con.Close();

                }
                catch (Exception ex)
                {
                    message = ex.Message.ToString();
                }
                if (message == "1")
                {
                    MainWindow mainWindow = new MainWindow();
                    mainWindow.Show();
                    WindowManager.CloseWindow(ViewID);

                }
                else
                   System.Windows.Forms.MessageBox.Show(message, "Info");
               
            }



        }

        private void IesireW()
        {
            WindowManager.CloseWindow(ViewID);
           
        }

        private void FillList()
        {
            try
            {
                con = new SqlConnection(connectionString);
                con.Open();
                cmd = new SqlCommand("select * from dbo.Users", con);
                adapter = new SqlDataAdapter(cmd);
                ds = new DataSet();
                adapter.Fill(ds, "dbo.Users");

                if (utilizatori == null)
                    utilizatori = new ObservableCollection();

                foreach (DataRow dr in ds.Tables[0].Rows)
                {
                    utilizatori.Add(new Utilizatori
                    {
                        id = Convert.ToInt32(dr[0].ToString()),
                        nume = dr[1].ToString(),
                        parola = dr[2].ToString(),
                        isadmin = bool.Parse(dr[3].ToString())
                    });
                }
            }
            catch (Exception ex)
            {
                System.Windows.Forms.MessageBox.Show(ex.Message);
            }
            finally
            {
                ds = null;
                adapter.Dispose();
                con.Close();
                con.Dispose();
            }
        }


        
        private void AdaugaP()
        {
            
            try
            {
                con = new SqlConnection(connectionString);
                con.Open();
                cmd = new SqlCommand("INSERT INTO dbo.Users(UsernAME, uSERpASS, IsAdmin) VALUES(@Nume, @Parola, @Eadmin);", con);

                SqlParameter numeNouP = new SqlParameter("@Nume", SqlDbType.NVarChar);
                numeNouP.Value = this.NumeNou;

                SqlParameter parolaNouP  = new SqlParameter("@Parola", SqlDbType.NVarChar);
                parolaNouP.Value = this.ParolaNou;

                SqlParameter eadminP = new SqlParameter("@Eadmin", SqlDbType.Bit);
                eadminP.Value = this.EadminNou;

                cmd.Parameters.Add(numeNouP);
                cmd.Parameters.Add(parolaNouP);
                cmd.Parameters.Add(eadminP);
                cmd.ExecuteScalar();
                //reader.Close();
                //reader.Dispose();
                cmd.Dispose();
                con.Close();
                
                System.Windows.Forms.MessageBox.Show("Adaugarea s-a facut cu succes!");
            }
            catch (Exception ex)
            {
                System.Windows.Forms.MessageBox.Show(ex.Message);
            }
            

        }



        private void ModificaUser()
        {

            try
            {
                con = new SqlConnection(connectionString);
                con.Open();
                cmd = new SqlCommand("UPDATE dbo.Users SET UsernAME=@Nume, uSERpASS=@Parola, IsAdmin=@Eadmin WHERE id=@Id", con);

                SqlParameter numeNouP = new SqlParameter("@Nume", SqlDbType.NVarChar);
                numeNouP.Value = utiliz.nume;

                SqlParameter parolaNouP = new SqlParameter("@Parola", SqlDbType.NVarChar);
                parolaNouP.Value = utiliz.parola;

                SqlParameter eadminP = new SqlParameter("@Eadmin", SqlDbType.Bit);
                eadminP.Value = utiliz.isadmin;

                SqlParameter IDD = new SqlParameter("@Id", SqlDbType.Int, 11);
                IDD.Value = utiliz.id;

                cmd.Parameters.Add(numeNouP);
                cmd.Parameters.Add(parolaNouP);
                cmd.Parameters.Add(eadminP);
                cmd.Parameters.Add(IDD);
                cmd.ExecuteScalar();
                //reader.Close();
                //reader.Dispose();
                cmd.Dispose();
                con.Close();

                System.Windows.Forms.MessageBox.Show("Modificarea s-a facut cu succes!");
            }
            catch (Exception ex)
            {
                System.Windows.Forms.MessageBox.Show(ex.Message);
            }



        }




        public void SelectedItem(Utilizatori utilizator)
        {
            txtSelectedItem = "Ati selectat " + utilizator.nume + "(ID: " + utilizator.id + ", cu parola : " + utilizator.parola + " care este admin: "+ utilizator.isadmin+")";
            OnPropertyChanged("txtSelectedItem");
        }

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

       

       
        #endregion
    }
}

public interface IRequireViewIdentification
{
    Guid ViewID { get; }
}

My view:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using user_management.Model;
using user_management.ViewModel;

namespace user_management
{
    /// 
    /// Interaction logic for MainWindow.xaml
    /// 
    public partial class MainWindow : Window
    {
        UtilizatoriViewModel ut;
        public MainWindow()
        {
            InitializeComponent();
            ut = new UtilizatoriViewModel();
            base.DataContext = ut;

        }

        private void lstBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var item = (ListBox)sender;
            ut.SelectedItem((Utilizatori)item.SelectedItem);
        }



    }
}

My XAML:

ListBox not updating on button click

Answers (1)

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