WPF invoke WCF dll periodically via DispatcherTimer

//WCF
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace WcfService1
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IBookService" in both code and config file together.
    [ServiceContract]
    public interface IBookService
    {
        [OperationContract]
        List<Book> GetBooksList(int cnt);
    }

    [DataContract]
    public class Book
    {
        [DataMember]
        public long Id { get; set; }

        [DataMember]
        public string Name { get; set; }

        [DataMember]
        public string ISBN { get; set;  }

        [DataMember]
        public string Author {  get; set; }

        [DataMember]
        public string Abstract {  get; set; }

        [DataMember]
        public string Comment { get; set; }

        [DataMember]
        public string Content {  get; set; }

        [DataMember]
        public string Summary {  get; set; }

        [DataMember]
        public string Title {  get; set; }

        [DataMember]
        public string Topic {  get; set; }

        public override string ToString()
        {
            return $"Id:{Id},Name:{Name},Author:{Author},ISBN:{ISBN}";
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.Threading;

namespace WcfService1
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "BookService" in code, svc and config file together.
    // NOTE: In order to launch WCF Test Client for testing this service, please select BookService.svc or BookService.svc.cs at the Solution Explorer and start debugging.
    public class BookService : IBookService
    {
        private static long idx = 0;
        private long GetIncrementIdx()
        {
            return Interlocked.Increment(ref idx);
        }
        public List<Book> GetBooksList(int cnt = 10000000)
        {
            List<Book> booksList = new List<Book>();
            for (int i = 0; i < cnt; i++)
            {
                long a = GetIncrementIdx();
                booksList.Add(new Book()
                {
                    Id = a,
                    Name = $"Name_{a}",
                    Author = $"Author_{a}",
                    Abstract = $"Abstract_{a}",
                    ISBN = $"ISBN_{a}",
                    Comment = $"Comment_{a}",
                    Content = $"Content_{a}",
                    Summary = $"Summary_{a}",
                    Title = $"Title_{a}",
                    Topic = $"Topic_{a}"
                });
            }
            return booksList;
        }
    }
}

//WPF
<Window x:Class="WpfApp25.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp25"
        mc:Ignorable="d"
        Title="{Binding MainTitle}" WindowState="Maximized">
    <Window.DataContext>
        <local:MainVM/>
    </Window.DataContext>
    <Grid>
        <DataGrid ItemsSource="{Binding BooksCollection}"
                  VirtualizingPanel.IsVirtualizing="True"
                  VirtualizingPanel.VirtualizationMode="Recycling"
                  VirtualizingPanel.CacheLength="5,5"
                  VirtualizingPanel.CacheLengthUnit="Item"
                  ScrollViewer.CanContentScroll="True"
                  ScrollViewer.IsDeferredScrollingEnabled="True"
                  UseLayoutRounding="True"
                  SnapsToDevicePixels="True"
                  EnableColumnVirtualization="True"
                  EnableRowVirtualization="True"
                  AutoGenerateColumns="True"
                  CanUserAddRows="False"
                  >
            <DataGrid.Resources>
                <Style TargetType="DataGridRow">
                    <Setter Property="FontSize" Value="20"/>
                    <Style.Triggers>
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter Property="FontSize" Value="30"/>
                            <Setter Property="Foreground" Value="Red"/>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </DataGrid.Resources>
        </DataGrid>
    </Grid>
</Window>
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Text;
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 System.Windows.Threading;
using WcfService1;

namespace WpfApp25
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }

    public class MainVM : INotifyPropertyChanged
    {
        private DispatcherTimer tmr;
        private BookService bkService;
        public MainVM()
        {
            bkService=new BookService(); 
            tmr=new DispatcherTimer();
            InitBooksCollection();
            tmr.Interval = TimeSpan.FromSeconds(20);
            tmr.Tick += Tmr_Tick;
            tmr.Start();
        }

        private void Tmr_Tick(object? sender, EventArgs e)
        {
            InitBooksCollection();
        }

        private void InitBooksCollection()
        {
            BooksCollection = new ObservableCollection<Book>(bkService.GetBooksList());
            MainTitle = $"{DateTime.Now},First Id:{BooksCollection.FirstOrDefault().Id},Last Id:{BooksCollection.LastOrDefault().Id}";
        }

        private string mainTitle=$"{DateTime.Now},loading...";
        public string MainTitle
        {
            get
            {
                return mainTitle;
            }
            set
            {
                if (value != mainTitle)
                {
                    mainTitle = value;
                    OnPropertyChanged();
                }
            }
        }

        private ObservableCollection<Book> booksCollection;
        public ObservableCollection<Book> BooksCollection
        {
            get
            {
                return booksCollection;
            }
            set
            {
                if(value!=booksCollection)
                {
                    booksCollection = value;
                    OnPropertyChanged();
                }
            }
        }
        public event PropertyChangedEventHandler? PropertyChanged;
        private void OnPropertyChanged([CallerMemberName]string propertyName="")
        {
            var handler = PropertyChanged;
            handler?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}