Как я могу обновить свой набор данных в WPF

I have this problem when I put the Binding Mode to TwoWay the DataGrid won't show. When I leave the Binding Mode as it is on default, the DataGrid will apear as strings, and I cannot find the problem. In XAML I have 3 more buttons: Load(that loads the table), Update and Cancel(that cancel all the changes and reloads the DataGrid directly from ObservableCollection.

<DataGrid x:Name="dataGrid" AutoGenerateColumns="True" Canvas.Left="10" Canvas.Top="10" AlternatingRowBackground="LightGreen" Height="245" Width="500" ItemsSource="{Binding Userss.UserCol, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" DataContext="{Binding RelativeSource={RelativeSource Self}}"/>

<pre lang="C#">public class Userss : INotifyPropertyChanged
{
    public static SQLiteConnection m_dd = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");

    private static ObservableCollection<userss> userCol = new ObservableCollection<userss>();

        public ObservableCollection<userss> UserCol
        {
            get { return userCol; }
            set
            {
                userCol = value;
                RaisePropertyChanged();
            }
        }
    public int Id { get; set; }
    private string _name;
    public string Name
    {
        get { return _name; }
        set
        {
            _name = value;
            RaisePropertyChanged();
        }
    }

    private Sex _sex;
    public Sex Sex
    {
        get { return _sex; }
        set
        {
            _sex = value;
            RaisePropertyChanged();
        }
    }

    private Stations _station;
    public Stations Station
    {
        get { return _station; }
        set
        {
            _station = value;
            RaisePropertyChanged();
        }
    }

    private Jobs _job;
    public Jobs Job
    {
        get { return _job; }
        set
        {
            _job = value;
            RaisePropertyChanged();
        }
    }

    private DateTime _date;
    public DateTime Date
    {
        get { return _date; }
        set
        {
            _date = value;
            RaisePropertyChanged();
        }
    }

    public static ObservableCollection<Userss> GetValues()
    {
        m_dd.Open();
        string sql = "select * from user";
        userCol.Clear();
        SQLiteCommand cmd = new SQLiteCommand(sql, m_dd);
        SQLiteDataReader reader = cmd.ExecuteReader();
        while (reader.Read())
        {
            string sex1 = reader["sex"].ToString();
            string station1 = reader["station"].ToString();
            string job1 = reader["job"].ToString();
            string data1 = reader["date"].ToString();
            userCol.Add(new Userss()
            {
                Id = Convert.ToInt32(reader["id"]),
                Name = reader["name"].ToString(),
                Sex = (Sex)Enum.Parse(typeof(Sex), sex1),
                Station = (Stations)Enum.Parse(typeof(Stations), station1),
                Job = (Jobs)Enum.Parse(typeof(Jobs), job1),
                Date = Convert.ToDateTime(data1)
            });
        }
        m_dd.Close();
        return userCol;

    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void RaisePropertyChanged([CallerMemberName] string caller = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(caller));
        }
    }
}

public enum Sex
{
    Male,
    Female
}
public enum Jobs
{
    Programmer,
    Designer,
    Manager,
    CTO,
    CEO,
}
public enum Stations
{
    Desktop,
    Laptop,
    Tablet
}

And here is my implementation for my MainWindow:

public partial class MainWindow : Window
    {
        public SQLiteConnection m_db = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");
        SQLiteDataAdapter adap;
        DataSet ds;
        DataTable dt;
        SQLiteCommandBuilder cmdbl;
        string Query;
        public MainWindow()
        {
            InitializeComponent();
        }
        private void LoadButton_Click(object sender, RoutedEventArgs e)
        {
            dataGrid.ItemsSource = Userss.GetValues();
        }

        private void Update_Click(object sender, RoutedEventArgs e)
        {
            if (MessageBox.Show("Are you sure you want to make those changes?", "Please confirm", MessageBoxButton.YesNo) == MessageBoxResult.Yes)
            {
                try
                {
                    m_db.Open();
                    cmdbl = new SQLiteCommandBuilder(adap);
                    Query = "Select * from user";
                    adap = new SQLiteDataAdapter(Query, m_db);
                    ds = new DataSet();
                    adap.Fill(ds, "Users");
                    dt = ds.Tables[0];
                    ds.Tables[0].AcceptChanges();
                    adap.Update(ds, "Users");
                    dt.AcceptChanges();
                    adap.Update(dt);
                    dataGrid.Items.Refresh();
                    m_db.Close();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
                
            }
            else
                this.dataGrid.CancelEdit();
        }

        private void CancelClick(object sender, RoutedEventArgs e)
        {
            if (MessageBox.Show("Are you sure you want to cancel those changes?", "Please confirm", MessageBoxButton.YesNo) == MessageBoxResult.Yes)
            {
                dataGrid.ItemsSource = Userss.GetValues();
            }
            else
                this.dataGrid.CancelEdit();
        }
    }
}

Btw I work in WPF.

Hope someone can help me. Thanks.

I've tryed to debug and see what is happening with the dataset and data table and I saw that they don't change at all.